SYSTEMS AND METHODS FOR BEAMFORMING FEEDBACK IN mmWAVE WIRELESS LOCAL AREA NETWORKS

ABSTRACT

A method implemented by an apparatus having multiple antennas includes determining information that is associated with a baseband channel. The information indicating any of: measurement information and channel information. The apparatus transmits a signal for requesting baseband beam tracking. The signal transmission is based on a determination that system performance is degraded in a beamforming transmission and re-estimation of the baseband channel is part of a current link adaptation procedure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.17/093,924 filed Nov. 10, 2020, which is a Continuation of U.S. patentapplication Ser. No. 16/300,263 filed Nov. 9, 2018, which is a NationalStage Application filed under 35 U.S.C. § 371 of InternationalApplication No. PCT/US17/31829, filed May 9, 2017, which issued underU.S. Pat. No. 10,855,350 on Dec. 1, 2022, and claims the benefit of U.S.Provisional Application No. 62/501,615, filed May 4, 2017, U.S.Provisional Application No. 62/445,639, filed Jan. 12, 2017, U.S.Provisional Application No. 62/365,281, filed Jul. 21, 2016, and U.S.Provisional Application 62/335,519, filed May 12, 2016, the contents ofeach of which are incorporated by reference herein.

TECHNICAL FIELD

This disclosure relates to systems and methods for beamforming trainingin wireless local area networks (WLANs), such as Institute of Electricaland Electronics Engineers (IEEE) 802.11ay WLANs.

BACKGROUND

Countless devices and networks around the globe operate according to oneor more IEEE 802.11 standards for engaging in wireless communications.These communications typically occur in the 2.4-GHz and 5-GHz bands,though other bands are used as well.

OVERVIEW OF DISCLOSED EMBODIMENTS

Presently disclosed are systems and methods for beamforming training inWLANs.

One embodiment takes the form of a method comprising an initiator devicetransmitting, to one or more responder devices, a plurality ofbeamforming frames for beamforming training wherein the initiator devicesweeps the transmissions through all beams in all sectors to provide anexhaustive beam refinement transmission. Alternative embodiments includea responder receiving a plurality of beamforming training frames; and,the responder transmitting a feedback frame including receive sector IDparameter and a receive antenna ID parameter.

Still further embodiments include a multistage beamforming trainingmethod comprising an initiator transmitting a first stage beamformingsignal comprising a sweep through all the transmit beams and a respondersweeping through all receive beams and responsively identifying a firstpair of beams. Other embodiments further comprise iteratively sweepingthrough additional beams and responsively estimating the next best pairgiven the first pair of beams.

Moreover, any of the variations and permutations described in thisdisclosure can be implemented with respect to any embodiments, includingwith respect to any method embodiments and with respect to any systemembodiments. Furthermore, this flexibility and cross-applicability ofembodiments is present in spite of the use of slightly differentlanguage (e.g., process, method, steps, functions, set of functions, andthe like) to describe and or characterize such embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts PPDU formats for 802.11ad.

FIG. 2 depicts an example transmission block diagram.

FIG. 3 depicts an example sector level sweep (SLS) training procedure.

FIG. 4 depicts an example sector sweep (SSW) frame format.

FIG. 5 depicts an example SSW-field format.

FIG. 6A depicts a first example SSW-feedback-field format, in accordancewith at least one embodiment.

FIG. 6B depicts a second example SSW-feedback-field format, inaccordance with at least one embodiment.

FIG. 7 depicts a first example packet structure for use with a beamrefinement protocol.

FIG. 8 depicts an 802.11ay PPDU format structure.

FIG. 9 depicts a device architecture having all physical antennasexcited by all the weights.

FIG. 10 depicts a second architecture having different Pas excited byseparate weights.

FIG. 11 depicts a cumulative distribution function of the average valuesof two off-diagonal entries of an HH^(H) matrix.

FIG. 12A depicts one embodiment of a Phase 2 MIMO phase.

FIG. 12B depicts a sequence diagram for one embodiment of Phase 1 andPhase 2 frame transmission.

FIG. 13 depicts the link capacity as a function for beam refinementlevel.

FIG. 14 depicts the link capacity gain of a closed loop SU-MIMO overopen loop.

FIGS. 15A-15E depicts 802.11ay configurations 1 through 5.

FIG. 16 depicts an exemplary embodiment of channel taps reported asin-phase and quadrature component pairs.

FIG. 17 depicts one embodiment of Phase 3 tracking for SU-MIMO in802.11ay.

FIG. 18 depicts one embodiment of Phase 3 tracking for MU-MIMO in802.11ay.

FIG. 19 depicts one embodiment of TRN based training.

FIG. 20 depicts one embodiment of frames for multiple MU-MIMOconfigurations.

FIG. 21A depicts an exemplary procedure for Phase 3 with setup and ACK:Polling based feedback.

FIG. 21B depicts an exemplary procedure for Phase 3 with polling but nosetup, where the existing configuration is used.

FIG. 22 depicts an exemplary procedure for Phase 3 with UL OFDMA/MIMOfeedback.

FIG. 23 depicts an exemplary procedure for Phase 3 with UL OFDMA/MIMOfeedback and no setup frame.

FIG. 24 depicts an exemplary beam tracking procedure with the initiatorrequesting TRN-T.

FIG. 25 depicts exemplary beam tracking for 802.11ay, in accordance withat least one embodiment.

FIG. 26 depicts an exemplary analog EDMG initiator receive beamtracking.

FIG. 27 depicts an exemplary Baseband EDMG initiator receive beamtracking.

FIG. 28 depicts an exemplary Analog EDMG initiator transmit beamtracking.

FIG. 29 depicts an exemplary Baseband EDMG initiator transmit beamtracking.

FIG. 30 depicts an exemplary Analog EDMG responder receive beamtracking.

FIG. 31 depicts an exemplary Baseband beam tracking with no TRN-Rfields.

FIG. 32 depicts an exemplary Baseband beam tracking with N TRN-R fields.

FIG. 33 depicts an exemplary packet structure for an Analog EDMGInitiator Receive Beam Tracking.

FIG. 34 depicts an exemplary packet structure for a Baseband EDMGInitiator Receive Beam Tracking.

FIG. 35 depicts an exemplary Baseband beam tracking with no TRN-TFields.

FIG. 36 depicts an exemplary Baseband beam tracking with N TRN-T Fields.

FIG. 37 depicts an exemplary packet structure for an Analog EDMGInitiator Transmit Beam Tracking.

FIG. 38 depicts an exemplary packet structure for a Baseband EDMGInitiator Transmit Beam Tracking.

FIG. 39 depicts an exemplary packet structure for an Analog EDMGResponder Receive Beam Tracking.

FIG. 40 depicts an example wireless-communication device, in accordancewith at least one embodiment.

FIG. 41 depicts a beam tracking method in accordance with at least oneembodiment.

FIG. 42 depicts a further beam tracking method in furtherance of themethod of FIG. 27 .

Moreover, before proceeding with this disclosure, it is noted that theentities, connections, arrangements, and the like that are depictedin—and described in connection with—the various figures are presented byway of example and not by way of limitation. As such, any and allstatements or other indications as to what a particular figure“depicts,” what a particular element or entity in a particular figure“is” or “has,” and any and all similar statements—that may in isolationand out of context be read as absolute and therefore limiting—can onlyproperly be read as being constructively preceded by a clause such as“In at least one embodiment . . . .” And it is for reasons akin tobrevity and clarity of presentation that this implied leading clause isnot repeated ad nauseum in the below detailed description of thedrawings.

DETAILED DESCRIPTION WLANs

Overview of WLAN Systems.

A WLAN in Infrastructure Basic Service Set (BSS) mode has an AccessPoint/Personal BSS (PBSS) Control Point (AP/PCP) for the BSS and one ormore stations (STAs) (e.g., client devices) associated with the AP/PCP.The AP/PCP typically has access or interface to a Distribution System(DS) or another type of wired/wireless network that carries traffic inand out of the BSS. Traffic to STAs that originates from outside the BSSarrives through the AP/PCP and is delivered to the STAs. Trafficoriginating from STAs to destinations outside the BSS is sent to theAP/PCP to be delivered to the respective destinations. Traffic betweenSTAs within the BSS may also be sent through the AP/PCP where the sourceSTA sends traffic to the AP/PCP and the AP/PCP delivers the traffic tothe destination STA. Such traffic between STAs within a BSS is reallypeer-to-peer traffic. Such peer-to-peer traffic may also be sentdirectly between the source and destination STAs with a direct linksetup (DLS) using an 802.11e DLS or an 802.11z tunneled DLS (TDLS). AWLAN using an Independent BSS (IBSS) mode has no AP, and compatibledevices simply communicate directly with each other. This mode ofcommunication is referred to as an “ad-hoc” mode of communication.

Using the 802.11ac infrastructure mode of operation, the AP/PCP maytransmit a beacon on a fixed channel, usually the primary channel. Thischannel may be 20 megahertz (MHz) wide, and is the operating channel ofthe BSS. This channel is also used by the STAs to establish a connectionwith the AP/PCP. The fundamental channel-access mechanism in an 802.11system is Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA). In this mode of operation, every STA, including the AP/PCP,will sense the primary channel. If the channel is detected to be busy,the STA backs off. Hence only one STA may transmit at any given time ina given BSS.

In 802.11n [1], High Throughput (HT) STAs may also use a 40-MHz-widechannel for communication. This is achieved by combining the primary20-MHz-wide channel with an adjacent 20-MHz-wide channel to form a40-MHz-wide contiguous channel.

In 802.11ac [2], Very High Throughput (VHT) STAs may support20-MHz-wide, 40-MHz-wide, 80-MHz-wide, and 160-MHz-wide channels. The40-MHz-wide channels and the 80-MHz-wide channels are formed bycombining contiguous 20-MHz-wide channels in a manner that is similar towhat is described above in connection with 802.11n. A 160-MHz-widechannel may be formed either by combining 8 contiguous 20-MHz-widechannels, or by combining 2 non-contiguous 80-MHz-wide channels in whatis also referred to at times as an “80+80 configuration.” For the 80+80configuration, the data, after channel encoding, is passed through asegment parser that divides it into two streams. Inverse Fast FourierTransform (IFFT) processing and time-domain processing are performed oneach stream separately. The streams are then mapped on to the twochannels, and the data is transmitted. At the receiver, this mechanismis reversed, and the combined data is delivered to the MAC of thereceiver.

Sub-1-gigahertz (GHz) modes of operation are supported by 802.11af [3]and 802.11ah [4]. For these specifications, the channel operatingbandwidths, as well as the carriers, are reduced relative to those usedin 802.11n [1] and 802.11ac [2]. 802.11af supports 5-MHz, 10-MHz, and20-MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ahsupports 1-MHz, 2-MHz, 4-MHz, 8-MHz, and 16-MHz bandwidths usingnon-TVWS spectrum. A possible use case for 802.11ah is support for MeterType Control (MTC) devices in a macro coverage area. MTC devices mayhave limited capabilities including only support for only limitedbandwidths, but also include a requirement for a very long battery life.

WLAN systems—such as 802.11n, 802.11ac, 802.11af, and 802.11ah—thatsupport multiple channels and multiple channel widths include a channelthat is designated as the primary channel. The primary channel may, butdoes not necessarily, have a bandwidth equal to the largest commonoperating bandwidth supported by all STAs in the BSS. The bandwidth ofthe primary channel is therefore limited by the STA (among the STAs thatare operating in a BSS) that supports the smallest bandwidth operatingmode (as the maximum supported channel-bandwidth operating mode for theparticular STA). In the example of 802.11ah, the primary channel may be1 MHz wide if there are STAs (e.g., MTC-type devices) that only supporta 1-MHz mode even if the AP/PCP and other STAs in the BSS support, e.g.,a 2-MHz, a 4-MHz, an 8-MHz, a 16-MHz, and/or one or more otherchannel-bandwidth operating modes in excess of the 1-MHzchannel-bandwidth operating mode. All carrier sensing, as well as NAVsettings, depend on the status of the primary channel; i.e., if theprimary channel is busy, for example, due to a STA that supports only a1-MHz operating mode currently transmitting to the AP, then the entireavailable frequency bands are considered busy even though majority of itstays idle and available.

In the United States, the available frequency bands that can be used for802.11ah are from 902 MHz to 928 MHz. In Korea, it is from 917.5 MHz to923.5 MHz; and in Japan, it is from 916.5 MHz to 927.5 MHz. The totalbandwidth available for 802.11ah is between 6 and 26 MHz depending onthe country code.

To improve spectral efficiency, 802.11ac has introduced the concept ofdownlink (DL) multi-user (MU) multiple-in-multiple-out (MIMO) (MU-MIMO)transmission to multiple STAs in the same symbol's time frame, e.g.,during a downlink OFDM symbol. The potential for the use of downlinkMU-MIMO is also currently considered for 802.11ah. One may note thatsince downlink MU-MIMO, as it is used in 802.11ac, uses the same symboltiming to multiple STAs, interference of the waveform transmissions tomultiple STAs is not an issue. However, all STAs involved in MU-MIMOtransmission with the AP/PCP must use the same channel or band, whichlimits the operating bandwidth to the smallest channel bandwidth that issupported by the STAs that are included in the MU-MIMO transmission withthe AP/PCP.

802.11ad

802.11ad is an amendment to the WLAN standard, which specifies the MACand PHY layers for very high throughput (VHT) in the 60 GHz band.

802.11ad has the following features:

-   -   1. 802.11ad supports data rates up to 7 gigabits (Gbits) per        second (s) (Gbits/s).    -   2. 802.11ad supports three different modulation modes:        -   a. Control PHY with single carrier and spread spectrum;        -   b. Single Carrier PHY; and        -   c. OFDM PHY.    -   3. 802.11ad uses the 60-gigahertz (GHz) unlicensed band, which        is available globally. At 60 GHz, the wavelength is 5        millimeters (mm), which makes compact antennas and antenna        arrays possible. Such an antenna can create narrow        radio-frequency (RF) beams at both the transmitter and the        receiver, which effectively increases the coverage range and        reduces interference.    -   4. 802.11ad has a frame structure that facilitates a mechanism        for beamforming training (discovery and tracking). The        beamforming training protocol includes two components: a sector        level sweep (SLS) procedure and a beam refinement protocol (BRP)        procedure. The SLS procedure is used for transmit beamforming        training; the BRP procedure enables receive beamforming training        as well as iterative refinement of both the transmit and receive        beams.

MIMO transmissions, including both single-user-(SU)-MIMO and MU-MIMO,are not supported by 802.11ad.

802.11ad PPDU Formats

Referring to FIG. 1 , 802.11ad supports three PPDU formats, which areControl PHY, Single Carrier (SC) PHY, and OFDM PHY PPDUs. The PPDUformats 50 are in FIG. 1 .

802.11ad Control PHY

Referring to FIG. 2 , Control PHY is defined in 802.11ad as the lowestdata rate transmission. Frames which have to be transmitted beforebeamforming training may use Control PHY PPDU. In 802.11ad, transmissiondiagram 100 of Control PHY is given in FIG. 2 .

Sector Level Sweep (SLS)

In FIG. 3 , an example SLS training procedure 110 is illustrated.

SLS training may be performed using a Beacon frame or SSW frame. Whenthe Beacon frame is utilized, the AP repeats the Beacon frame withmultiple beams/sectors within each Beacon interval (BI) and multipleSTAs can perform BF training simultaneously. However, due to the size ofBeacon frame, it is no guarantee that the AP can sweep all thesectors/beams within one BI. Thus, a STA may need to wait multiple BIsto complete ISS training, and latency may be an issue. A SSW frame 120may be utilized for point to point BF training. In FIG. 4 , A SSW framemay be transmitted using control PHY and the frame format is shown inFIG. 4 .

An example SSW-field structure (format) 130 is defined in FIG. 5 .

A first example SSW-feedback field 140 is shown in FIG. 6A. Thiscorresponds to when this is transmitted as part of an ISS.

A second example SSW-feedback field 150 is shown in FIG. 6B. Thiscorresponds to when this is not transmitted as part of an ISS.

Beam Refinement Protocol (BRP)

Beam refinement is a process where a STA can improve its antennaconfiguration (or antenna weight vectors) both for transmission andreception. In the beam refinement procedure, BRP packets are used totrain the receiver and transmitter antenna. There are two types of BRPpackets: BRP-RX packets and BRP-TX packets. Referring to FIG. 7 , a 160BRP packet may be carried by a DMG PPDU followed by a training fieldcontaining an AGC field and a transmitter or receiver training field asshown in FIG. 7 .

A value of N in FIG. 7 is the Training Length given in the header filed,which indicates that the AGC has 4N subfields and that the TRN-R/T fieldhas 5N subfields. The CE subfield is the same as the one in the preambledescribed in the previous section. All subfields in the beam trainingfield are transmitted using rotated π/2-BPSK modulation.

BRP MAC frame is an Action No ACK frame, which has the following fields:

-   -   Category    -   Unprotected DMG Action    -   Dialog Token    -   BRP Request field    -   DMG Beam Refinement element    -   Channel Measurement Feedback element 1    -   Channel Measurement Feedback element k

802.11ay (TGay)

Requirements of 802.11ay

Task Group ay (TGay), approved by IEEE in March 2015, is expected todevelop an amendment that defines standardized modifications to both theIEEE 802.11 physical layers (PHY) and the IEEE 802.11 medium accesscontrol layer (MAC) that enables at least one mode of operation capableof supporting a maximum throughput of at least 20 gigabits per second(measured at the MAC data service access point), while maintaining orimproving the power efficiency per station. This amendment also definesoperations for license-exempt bands above 45 GHz while ensuring backwardcompatibility and coexistence with legacy directional multi-gigabitstations (defined by IEEE 802.11ad-2012 amendment) operating in the sameband.

Although much higher maximum throughput than that of 802.11ad is theprimary goal of TGay, some members of the group also discussed includingmobility and outdoor support. More than ten different use cases areconsidered and analyzed in terms of throughput, latency, operationenvironment and applications [5].

Since 802.11ay will operate in the same band as legacy standards, it isrequired that the new technology will ensure backward compatibility andcoexistence with legacies in the same band.

802.1 lay PPDU Format

It has been agreed that 802.11ay PPDU contain legacy part and EDMG(Enhanced Directional Multi Bit) part. In FIG. 8 , the detailed PPDUformat 170 is illustrated. The L-STF, L-CEF, L-Header and EDMG-Header-Afields are transmitted using SC mode for backward compatibility. It hasbeen agreed in IEEE January 2016 meeting that:

For a control mode PPDU, the reserved bits 22 and 23 shall be both setto 1 to indicate the presence of the EDMG-Header-A field.

For a SC mode PPDU or an OFDM mode PPDU, the reserved bit 46 shall beset to 1 to indicate the presence of the EDMG-Header-A field.

Millimeter Wave Precoding

Precoding at millimeter wave frequencies may be digital, analog or ahybrid of digital and analog [6].

Digital precoding: Digital precoding is precise and can be combined withequalization. It enables single user (SU), multi-user (MU), andmulti-cell precoding, and is typically used in sub 6 GHz, for example inIEEE 802.11n and beyond and in 3GPP LTE and beyond. However, inmillimeter wave frequencies, the presence of a limited number of RFchains compared with antenna elements and the sparse nature of thechannel complicates the use of digital beamforming.

Analog Beamforming: Analog beamforming overcomes limited number of RFchains issue by using analog phase shifters on each antenna element. Itis used in IEEE 802.11ad during the Sector Level Sweep (which identifiesthe best sector), Beam Refinement (which refines the sector to anantenna beam), and beam tracking (which adjusts the sub-beams over timeto take into account any change in the channel) procedures. Analogbeamforming is also used in IEEE 802.15.3. In this case a binary searchbeam training algorithm using a layered multi-resolution beamformingcodebook is used. Analog beamforming is typically limited to singlestream transmission.

Hybrid beamforming: In hybrid beamforming, the precoder is dividedbetween analog and digital domains. Each domain has precoding andcombining matrices with different structural constraints, e.g., constantmodulus constraint for combining matrices in the analog domain. Thisdesign results in a compromise between hardware complexity and systemperformance. Hybrid beamforming may be able to achieve digital precodingperformance due to sparse nature of channel and supportmulti-user/multi-stream multiplexing. However, it is limited by numberof RF chains. This may not be an issue as mmWave channels are sparse inthe angular domain so this limitation may not be as important.

Multi-Antenna Analogue Beamforming Methods for 802.11ad+

Based on issues the analog beamforming found in IEEE 802.11ad, analogbeamforming methods for 802.11ad+/802.11ay have been discussed in [7].Implementations discussed include the following:

-   -   Spatial diversity with beam switching.    -   Spatial diversity with a single beam.    -   Weighted multipath beamforming training.    -   Beam division multiple access.    -   Single user spatial multiplexing.    -   Reduced beamforming training overhead

Two architectures are presented in [7], one with all physical antennas(PA) 180 excited by all the weights (shown in FIG. 9 ) while the secondhas different PAs 190 that are excited by separate weights (shown inFIG. 10 ).

In the present disclosure, embodiments for IEEE 802.11ad+/ay thatutilize combinations of analog and digital precoding (hybrid mmWaveprecoding) to enable multi-stream/multi-user transmission are described.

Open Loop Vs Closed Loop MIMO for Spatial Multiplexing

The MIMO techniques based on channel state information (CSI) arecommonly used in networks with multiple antennas at the transmitters andreceivers to improve the spectral efficiency. They are typicallyimplemented by using a CSI dependent precoder at the transmitter and amechanism to feedback the CSI measured at the receiver or, assumingreciprocity of the channel, at the transmitter during the reception offeedback of other information from the receiver. For mmW systems,however, it may be too complicated to implement the closed loop processdue to very wide bandwidth. Some may argue that, since in mmW system,the transmitter antenna can generate very narrow beams so that byaligning Tx and Rx antenna pairs there would be weak or no cross linkinterference between the beams. If this is the case, the MIMO channelmatrix would be in a diagonal form and, therefore, using open loopmultiplexing scheme would be sufficient. However, from simulationresults obtained using the scenarios defined in the 802.11ad channelmodel with the associated antenna configuration, the probability ofhaving a non-orthogonal channel matrix is very high. This means it wouldstill be beneficial to use closed loop (e.g., CSI based channelprecoding) MIMO schemes for spatial multiplexing. FIG. 11 shows thedistributions (Cumulative Distribution Function—CDF) of the absolutevalues of the off-diagonal terms (off-diagonal entries of HH^(H) matrix)of 1000 channel realizations for five different scenarios (cubical farlaptop, cubical near laptop, conference room STA to AP, conference roomSTA to STA, living room).

802.1 Lay MU-MIMO Beamforming Protocol Proposal

A beamforming protocol has been proposed to enable MU-MIMO in 802.11ay[8]. This Protocol is comprised of the following phases, executed inorder:

Phase 1: SISO phase (mandatory). Note that in this phase, the ShortSector Sweep (SSW) frame is used and a group ID may be used to addressmultiple STAs at once. Feedback is based on polling each individual ofthe group. A Channel Measurement Feedback element, or a modified versionof it, is included in the DMG SISO Setup Response frame and includeslist of received I-TXSS sectors/antennas and their correspondingSNR/RSSI per RX antenna.

Phase 2: MIMO phase (mandatory). The MIMO phase 200 comprises thefollowing sub-phases, which are also illustrated in FIG. 12A:

-   -   BF Setup: Initiator 210 transmits this setup information in        minimum set of frames in different antennas/sectors (sufficient        to reach all responders 220).    -   Initiator 210 transmits MU-MIMO BF training, which are BRP        frames with RX training fields appended.    -   Initiator polls MU-MIMO FBs (indicates FB formats and fields)        and responder responds with MU-MIMO feedbacks.    -   Initiator 210 transmit MU-MIMO selection for sets of MU        transmission configuration to all responders in minimum set of        frames (sufficient to reach all intended responders).

FIG. 12B illustrates a sequence diagram 230 for Phase 1 and Phase 2transmissions.

Dimensionality of BRP Feedback for 802.11ay

In 802.11ad, the BRP selects best effective channels and optionallyfeeds back the actual channel. It differs from SLS by allowing feedbackof all measurements.

Current 11ad feedback sends back the following dimensions:

-   -   PAA/eDMG antenna: captured in 802.11ad    -   Time or tap delay: captured in 802.11ad (see Table 1 below)    -   Channel    -   Measurement    -   Feedback Element        11ad

TABLE 1 Element ID Length SNR SNR1 8 bits SNR2 8 bits 8 bits SNR(Nmeasure) 8 bits Channel Measurement Chan Meas 1 Ntaps × 16 bits ChanMeas 2 Chan Meas (Nmeasure) Ntaps × 16 bits Tap Delay relative delay 1 8bits relative delay 2 8 bits 8 bits relative delay (Ntaps) 8 bits SectorID order sector ID1 6 bits Antenna ID1 2 bits sector ID (Nmeasure/Nbeam)6 bits antenna ID (Nmeasure/Nbeam) 2 bits

-   -   Nmeasure: number of TRN-T elements    -   Time dimension captured in Ntaps    -   PAA dimension captured in number of SNR elements sent

For 11ay, with the addition of polarization and the use of multipleantenna transmission, additional dimensions are fed back in someembodiments described herein. In addition, methods to reduce the amountof feedback are provided.

Enhanced BRP for 802.11ay

With the requirement for MIMO transmission, the BRP may be updated toenable identification of multiple beams from the sectors identified fromthe SLS or enhanced SLS. In addition, efficient feedback methods areprovided to enable the baseband channel identification to allow forprecoder design.

Baseband Feedback for SU-MIMO and MU-MIMO in 802.11ay Hybrid Beamforming

In hybrid beamforming, a baseband beamformer or precoder is used withthe analog beamformer to improve overall performance. In scenarios wherethere may be some change in the channel without any change in the analogbeamformer used, a feedback mechanism is described herein for feedbackof the effective channel without the need for an elaborate BRPprocedure. This relates to baseband tracking of the link. As an example,SISO and MIMO phases presented in [8] set up the analog transmission. Anadditional phase may be used to enable tracking of the baseband channelwithout the need to reinitiate the analog setup phases. Hybridbeamforming may include the product of the effective baseband channelHBB and the Baseband beamformer FBB. The hybrid beamforming may berepresented as shown below:

Y=HF _(A) F _(BB) x+n; wherein H _(BB) =HF _(A)

As shown above, H=the channel, H_(BB)=the effective baseband channel,F_(A)=the analog beamformer, F_(BB)=the Baseband beamformer, F=idealbaseband precoder, and FAF_(BB)=the hybrid beamformer. and theF_(A)F_(BB)≈F. In one case, the analog beamformer F_(A) and the basebandbeamformer F_(BB) may be unknown. The channel H may be estimated. Theideal baseband precoder F may be designed for the channel H. The designbetween the analog beamformer F_(A) and the baseband beamformer F_(BB)may be derived from the ideal baseband precoder F. In another case, theanalog beamformer F_(A) and the baseband beamformer F_(BB) may beunknown, and the channel H may be estimated. Further, the analogbeamformer F_(A) may be designed and the effective baseband channelH_(BB) may be calculated. The baseband beamformer F_(BB) may be designedfrom the effective baseband channel H_(BB). In yet another case, theanalog beamformer F_(A) and the baseband beamformer F_(BB) may beunknown. The effective baseband channel H_(BB) may be estimated, and thebaseband beamformer F_(BB) may be designed from the effective basebandchannel H_(BB). The present invention can estimate the effectivebaseband channel H_(BB) more efficiently by eliminating additionaltrain-to-receiver (TRN) fields from training packets sent from theinitiator 210 to the responder 220. In an optimized training packet,additional TRN Fields are eliminated to enable the effective basebandchannel H_(BB) to be estimated more efficiently. FIGS. 12A and 12B showoptimized training packets in which additional TRN fields are eliminatedto allow the effective baseband channel H_(BB) to be estimated moreefficiently. In some embodiments, the responder may comprise an analogbeamformer configured with previously determined analog beamcoefficients. The analog beamformer generates a beam-formed receivesignal by processing the received training packet with the previouslydetermined analog beam coefficients. The receiver portion of theresponder device may also include a packet processor. The packetprocessor is configured to identify the presence of a digital baseband(DBC) tracking parameter that indicates that the DBC tracking should beperformed. The responder may also include a baseband signal processorconfigured to determine a DBC estimate from a non-precoded trainingsignal within the beam-formed receive signal. In addition, the responderincludes a transmitter configured to transmit a feedback message havingtransmitter precoder data based on the DBC estimate.

Polled Feedback

In a scenario with multiple STAs, polling based feedback although simpleand robust, may be inefficient. To improve the efficiency, multiple STAsmay be polled simultaneously. Methods are disclosed herein to ensureproper separation and to manage the feedback in the cases where thelength of the response frames may be different. Note that the differencein response may be because of (a) the MCS used, and/or (b) a differencein the number of Rx antennas at the STA.

EMBODIMENTS

Enhanced Beam Refinement Protocol Procedures

To identify the multiple beams used at the transmitter and receiver increating a multiple antenna millimeter wave architecture and to identifythe direct and cross terms of the effective channel between them, thedisclosure herein describes improved baseline BRP procedure from thatproposed in 802.11ad and changes to the BRP feedback are provided formulti-antenna transmission. Described herein are multiple embodiments ofmethods to enhance the BRP, including:

Exhaustive Enhanced BRP: In this method, the initiator and responder maysweep through all transmit beams and receive beams in all the sectors.The responder may then feedback all channel elements and AP may then usethe feedback to construct channel at the transmitter.

Multi-stage Enhanced BRP: In this method, the initiator and respondermay sweep through all the transmit beams and receive beams and identifythe best pair. The best pair may then be fixed and thetransmitter/receiver sweep through all the other beams and estimate thenext best pair given the first pair. This procedure may be continuedtill the total number of streams desired is reached.

Exhaustive Enhanced BRP with multiple beam sweep: In this method, theinitiator and responder may sweep through groups of transmit beams andreceive beams (for example in pairs for a 2 stream transmission) in allthe sectors. The responder may feed back all the information or mayidentify and feedback only best beam groups. This is a hybrid betweenpure SLS and BRP.

FIG. 13 depicts the link capacity as a function of beam refinementlevel. To illustrate the benefits of the enhanced BRP procedure, FIG. 13shows the capacity in bps/Hz for an exhaustive two beam sweep system.The x-axis represents successive beam refinement levels where eachrefinement level is defined by the angle spanned and the beam width ofeach beam as shown in Table 2.

In this example, the beams are exhaustively searched with a multipleantenna metric. As can be seen, the achievable capacity increases withincreasing refinement. Table 2 below depicts the relationship betweenthe level of refinement and corresponding angle span and beam width

TABLE 2 V-Pol H-Pol Level Span Beamwidth Span beamwidth 1 180 45 360 3602 180 45 180 45 3 90 22.5 180 45 4 90 22.5 90 22.5 5 45 11.25 90 22.5 645 11.25 45 11.25 7 22.5 5.625 45 11.25 8 22.5 5.625 22.5 5.625

FIG. 14 shows the link capacity gain of closed loop SU-MIMO over openloop for antenna configuration #3 with circular polarized antenna. Cases1-5 of FIGS. 15A-15E represent scenarios: 1) cubical far laptop, 2)cubical near laptop, 3) conference room station to AP, 4) conferenceroom station to station, and 5) living room. These results show that theclosed loop SU-MIMO could provide up to 50% more capacity gain than openloop SU-MIMO.

From the results shown FIG. 14 , proper feedback may be desirable toprovide a digital precoder that exploits the cross terms obtained in theMIMO channel from the analog beamformer.

Feedback Dimensionality and 802.11ay Configurations

In 802.11ad, the PAA/eDMG and time or tap delay are captured in the BRPfeedback. Each beam, PAA, eDMG antenna array or channel measurementfeeds back N complex time or tap delays. To enable proper feedback in802.11ay, methods described herein capture the additional dimensionalityobtained by the allowance of multiple stream transmission (eitherthrough the use of channel components arriving at the same PAA fromdifferent directions, channel components arriving on differentpolarizations or channel components arriving at different PAAs/eDMGantennas). Further embodiments provide additional feedback dimensions tocapture the use of antenna polarization and/or the use of multiple PAAssimultaneously during a transmission.

-   -   a. If both polarizations are present, the effective channel is        2×2 per time dimension (to capture the cross polarization        discrimination (xPD).    -   b. if vertical or horizontal polarization only is present, the        effective channel is 1×1 per time dimension.    -   c. Note that for a multiple PAA configuration, the polarization        and PAA dimensions may be collapsed. As an example, in        configuration #4,the system may utilize 4×4 complex feedback.

To illustrate the additional feedback dimensions provided herein, theconfigurations that have been discussed in the 802.11ay will bedescribed and embodiments having the dimensions applicable for eachconfiguration are described.

Configuration 1 of FIG. 15A:

In this configuration, each element has a single polarization (Verticalor Horizontal). Multiple stream transmission is created by directingbeams to channel components that arrive from different directions (andarrive at different tap delays). Array 1105, signal streams 1114, 1116,phase shifter 1120, and PAA element 1110 are illustrated. Further,devices 1124 b, 1128 b, and signal beams 1126 b and 1130 b areillustrated. In addition, devices 1124 a, 1128 a and beams 1126 a and1130 a are illustrated. The beams having polarizations V, H. In thiscase the dimensionality is

1×1 per time dimension, per PAA

Overall: 1×1 per time dimension

Configuration 2 of FIG. 158

In this configuration, each element has dual polarization (vertical andhorizontal). Multiple stream transmission is created by directing beamsto channel components that arrive from different directions (and arriveat different tap delays) and arrive on different polarizations. Devices1124 c, 1128 c, and polarizations 1126 c and 1130 c are illustrated.Further, devices 1124 d and 1128 d and beams 1126 d and 1130 d areillustrated. In addition, devices 1124 f, 1128 f, and beams 1126 f and1130 f are illustrated. FIG. 15B also illustrates devices 1124 e, 1128e, and beams 1126 e and 1130 e. The beams having polarizations V,H. Inthis case the dimensionality is

×2 per time dimension, per PAA

Overall: 2×2 per time dimension

Configuration 3 of FIG. 15C

In this configuration, each element has vertical or horizontalpolarization V, H with multiple PAAs. Multiple stream transmission iscreated by directing beams between PAAs. The channel components on eachPAA may arrive from different directions (and arrive at different tapdelays). FIG. 15C illustrates array centers 1105 a, 1105 b. FIG. 15Calso illustrates devices 1124 g, 1128 g, and beams 1126 g, 1130 g.Further, devices 1124 h, 1128 h and beams 1124 h, 1130 h areillustrated. In addition, devices 1124 i, 1128 i and beams 1126 i, 1130i are illustrated. FIG. 15C also illustrates devices 1124 j, 1128 j, andbeams 1126 j, 1130 j. The beams having polarizations V, H. A distancedbetween array centers 1105 a, 1105 b is also illustrated. In this casethe dimensionality is

1×1 per time dimension, per PAA

Overall: 2×2 per time dimension

Configuration 4 of FIG. 15D

In this configuration, each element has dual polarization (vertical andhorizontal) with multiple PAAs. Multiple stream transmission is createdby directing beams to channel components that arrive from differentdirections (and arrive at different tap delays) and arrive on differentpolarizations from the different PAAs. FIG. 15D illustrates signalstreams 1215, 1217. Further, devices 1124 k, 1128 k, and beams 1126 k,1127 k, 1130 k and 1131 k. Further, devices 1124 l, 1128 l and beams1126 l, 1127 l, 1130 l and 1131 l are illustrated. In addition, devices1124 m, 1128 m, beams 1126 m, 1127 m and beams 1130 m, 1131 m areillustrated. FIG. 15D also illustrates devices 1124 n, 1128 n, and beams1126 n, 1127 n, 1130 n, and 1131 n. The beams have polarizations V, H.In this case the dimensionality is

×2 per time dimension, per PAA

Overall: 4×4 per time dimension

Configuration 5 of FIG. 15E

In this configuration, each element at the transmitter has vertical orhorizontal polarization while each element at the receiver is dualpolarized. FIG. 15E illustrates arrays 1206, 1207. Further, devices 1124p, 1128 p and beam 1126 p are illustrated. In addition, devices 11240,1128 o and beams 1126 o are illustrated. The beams have polarizations V,H. In this case, the transmission is single stream with multi-dimensionreception at the reception. In this case the dimensionality is

1×2 per time dimension, per PAA (SIMO)

Overall: 1×2 per time dimension

Feedback for Exhaustive Search eBRP in Configuration #1

In this embodiment, described are feedback methods for exhaustive searchBRP. In exhaustive search BRP, the initiator and responder may sweepthrough all combinations of transmit beams and receive beams in thesectors or beams selected by previous sector level sweep procedures orbeam refinement procedures.

The BRP procedure may feed back all channel the direct and cross channelelements and the initiator may use the feedback to construct channel atthe transmitter for further baseband precoder design. The updatedfeedback for a configuration #1 scenario is shown below:

-   -   Feedback characteristics        -   element is 1×1        -   Time dimension captured by tap delay        -   May utilize implicit or explicit identification of receive            beam due to the multiple streams.

Exemplary feedback for exhaustive search is shown below in Table 3 withthe additional feedback elements shown in boldface:

Exhaustive BRP (All Tx

beams, All Rx beams)

TABLE 3 Element ID Length SNR SNR1 8 bits SNR2 8 bits 8 bits SNR(Nmeasure) 8 bits Channel Chan Meas 1 Ntaps × 16 bits Measurement ChanMeas 2 Chan Meas (Nmeasure) Ntaps × 16 bits Tap Delay relative delay 1 8bits relative delay 2 8 bits 8 bits relative delay (taps) 8 bits SectorID order Tx sector ID1 6 bits Tx Antenna ID1 2 bits Rx sector ID1 6 bitsRx antenna ID1 2 bits Tx sector ID (Nmeasure/Nbeam) 6 bits Tx antenna ID(Nmeasure/Nbeam) 2 bits Rx sector ID (Nmeasure/Nbeam) 6 bits Rx antennaID (Nmeasure/Nbeam) 2 bits

In one embodiment, each channel tap is reported as an in-phase andquadrature component pair, with each component value represented as atwos complement number between −128 and 127. This is illustrated inTable 4 below:

TABLE 4 Field Size Meaning Relative I Nr × Nt × The in-phase componentof the MIMO Component 8 bits impulse response for Tap #1, relative toTap #1 amplitude of strongest I or Q measured Relative Q Nr × Nt × Thequadrature component of the MIMO Component 8 bits impulse response forTap #1, relative to Tap #1 amplitude of strongest I or Q measured

An example is shown in FIG. 16 .

As the beam refinement levels increase, the difference between thechannel measured at the previous and current level decreases. As such,differential or progressive feedback may result in feedback overheadreduction as the beam width reduces and the channel approaches the realchannel. Reduction in the overhead may also be beneficial for beamtracking.

In this embodiment, fields are provided to:

-   -   (a) Dynamically change the size of the bit width of the channel        feedback. This may be indicated in one or more additional        field(s).    -   (b) Indicate that the channel measurement field is differential.        Note that additional fields are provided in some embodiments to        indicate the TxID and RxID pair that forms the baseline for the        differential. In this example, the additional 16 bits signaled        for the basis combined with the reduction in bitwidth per        channel tap feedback may result in a reduction in the overall        feedback.

In differential feedback, the STA feeds back the difference between theprevious and current channel measurements. As the difference decreases,the feedback may be captured by smaller bit widths. In this case, thebitwidth of the feedback may be fed back. Note that for the differentialfeedback scenario, the original and differential feedback may beexplicit representations of the original and difference channel.

In progressive feedback, the STA feeds back an index from a codebookthat represents the difference between the previous and current channelmeasurements. As the difference decreases, the feedback may be capturedby a smaller codebook. In this case, multiple codebooks may be definedand the codebook the feedback maps to may have to be fed back. Note thatfor the progressive feedback scenario, the original and progressivefeedback may be implicit representations of the original and differencechannels represented by various codebooks.

To enable differential or progressive feedback for a mm Wave system thefollowing elements are defined for use in some embodiments: theinformation fed back; the information feedback type; and the baselinereference.

For the information fed back:

-   -   a. Differential information may be the SNR, the channel        measurement, the tap delay and the sector ID of the baseline        feedback.    -   b. In one example, the differential information fed back may be        fixed and specified by a standard (e.g., SNR, channel        measurement and/or tap delay).    -   c. In one example, the differential feedback information may be        adaptively selected. Feedback frames may be defined that        indicate the specific differential information fed back.    -   d. In one example, a 3-bit signaling field may be defined that        indicates the specific information and the order in which the        information is fed back.

For the information feedback type:

-   -   a. Given that there are three information types, both        instantaneous and differential/progressive feedback may be used.        For example, the SNR and channel feedback may be differential        while the tap delay feedback may be original.    -   b. Signaling may be needed to indicate the information feedback        type in this case.

For the baseline reference:

-   -   a. Differential or progressive feedback requires a baseline for        comparison.    -   b. In one embodiment, the difference may be based in time, where        feedback frames refer to previously fed back frames as the        baseline. In this case, the feedback is not self-contained and        may result in error propagation if one of the feedback frames in        the sequence is lost.        -   i. It may be assumed that, in this case, the sector order ID            and/or tap delay do not change, and so may not be fed back            for overhead reduction.

Table 5 below shows an exemplary frame with adaptive absolute anddifferential/progressive feedback.

TABLE 5 Exemplary Adaptive Absolute and Differential/ProgressiveFeedback Element ID Length Type SNR, Channel Measurement, delay Size SNRdifferential feedback 3 size/codebook index Size Channel differentialfeedback 3 Measurement size/codebook index Size Delay differentialfeedback 2 size/codebook index SNR type absolute/differential Channelabsolute/differential measurement Type Delay Type absolute/differentialSNR SNR1 3 bits SNR2 3 bits 3 bits SNR (Nmeasure) 3 bits Channel ChanMeas 1/Chan codeword 1 Ntaps × 3 bits Measurement Chan Meas 2/Chancodeword 2 Chan Meas (Nmeasure)/Chan Ntaps × 3 bits codeword (Nmeasure)Tap Delay relative delay 1 2 bits relative delay 2 2 bits 2 bitsrelative delay (taps) 2 bits Sector ID order Tx sector ID1 6 bits TxAntenna ID1 2 bits Rx sector ID1 6 bits Rx antenna ID1 2 bits Tx sectorID (Nmeasure/Nbeam) 6 bits Tx antenna ID (Nmease/Nbeam) 2 bits Rx sectorID (Nmeasure/Nbeam) 6 bits Rx antenna ID (Nmease/Nbeam) 2 bits

The tables (6, 7 and 8) below show exemplary frames for SNR, channelmeasurement and delay with single information differential feedback andimplicit baseline referencing. The receiver assumes that other elementsof feedback remain the same.

TABLE 6 Exemplary SNR differential feedback Element ID Length Type SNRSize Size of differential feedback 2 bits SNR SNR1 2 bits SNR2 SNR(Nmeasure) 2 bits

TABLE 7 Exemplary SNR channel measurement feedback Element ID LengthType Chan Meas Size Size of differential feedback 2 bits ChannelMeasurement Chan Meas 1 Ntaps × 2 bits Chan Meas 2 Chan Meas (Nmeasure)Ntaps × 2 bits

TABLE 8 Exemplary relative delay differential feedback Element ID LengthType Relative delay Size Size of differential feedback 3 bits Tap Delayrelative delay 1 3 bits relative delay 2 3 bits 3 bits relative delay(taps) 3 bits

Feedback for Multi-Stage eBRP in Config #1

In this embodiment, we present feedback methods for multi-stage BRP. Inthe multi-stage BRP, within each BRP, the initiator and responder mayselect the best transmit and receive beams in stages rather thanperforming an exhaustive search.

In the first stage, they identify the best transmit receive pair. Theythen fix the best pair and find the next best pair given the first. Thiscontinues till the total number of pairs desired is reached.

The updated feedback for a configuration #1 scenario is describedherein.

This embodiment includes feedback methods for exhaustive search BRP. Inexhaustive search BRP, the initiator and responder may sweep through alltransmit beams and receive beams in the sectors or beams selected byprevious sector level sweep procedures or beam refinement procedures.

The BRP procedure may feed back all channel the direct and cross channelelements and the initiator may use the feedback to construct channel atthe transmitter for further baseband precoder design. The updatedfeedback for a configuration #1 scenario is shown below:

-   -   a. Feedback for stage 1 with all Tx beams        -   i. Element is 1×1; time is captured in the tap delay        -   ii. Provide either implicit or explicit Rx beam            identification    -   b. Feedback and fix best Tx/Rx beam    -   c. Feedback for stage 2: BRP for other beams with first fixed        -   i. Embodiment 1: Element is 2×2; time is captured in the tap            delay        -   ii. Embodiment 2: Stage 1 Beam stores all the cross beam            channels. On feedback of a 1×2 channel for during stage 2,            the MIMO channel can be constructed        -   iii. Provide Rx beam identification    -   d. Select best MIMO channel    -   e. Example feedback shown below in Table 9, for example        multi-stage eBRP feedback:

BRP for all Tx

beams, single Rxbeam (step 1)

TABLE 9 Element ID Length SNR SNR1 8 bits SNR2 9 bits 10 bits  SNR(Nmeasure) 11 bits  Channel Measurement Chan Meas 1 Ntaps × 16 bits ChanMeas 2 Chan Meas (Nmeasure) Ntaps × 16 bits Tap Delay relative delay 1 8bits relative delay 2 8 bits 8 bits relative delay (Nmeasure) 8 bitsSector ID order Tx sector ID1 6 bits Tx Antenna ID1 2 bits Rx sector ID1Rx antenna ID1 Tx sector ID (Nmeasure/Nbeam) Tx antenna ID(Nmease/Nbeam) Rx sector ID (Nmeasure/Nbeam) 6 bits

Note that the differential and progressive feedback may be used perstage. In one example, stage 1 may use non-differential feedback thenstage 2 may be repeated multiple times with the first timenon-differential and the subsequent times differential.

Feedback for Exhaustive eBRP with Multiple Beam Sweep in Config #1

As opposed to the exhaustive search method in which a single beam isswept through, the system may sweep through N beams simultaneously. Inthis case, the feedback is also modified to take the N simultaneousbeams into consideration. The following procedure may be followed:

-   -   a. AP indicates to STA that it supports 2×2 system    -   b. AP will send TRN-T with 2 orthogonal beams    -   c. STA will sweep through 2-Rx beams per TRN-T element.        -   i. calculate and communicate this information    -   d. Feedback        -   i. SNR/Capacity feedback is for the MIMO channel        -   ii. Element is 2×2 per time delay        -   iii. Provide 2 Rx beam identification        -   iv. Embodiments may feedback all or best

Exemplary Feedback is shown below in Tables 10A and 10B for exhaustiveeBRP with multiple beam sweep:

BRP for all pairs ofTx beam, all pairs ofRx beamssetup Ntx_beams x

TABLE 10A Element ID Length SNR SNR1_eff; Cap_eff1 8 bits SNR2_eff;Cap_eff2 8 bits 8 bits SNR3_eff; Cap_eff3 (Nmeasure) 8 bits Channel ChanMeas 1 Ntaps × 2 × Measurement Chan Meas 2 2 × 16 bits Chan Meas(Nmeasure) Ntaps × 2 × 2 × 16 bits Tap Delay relative delay 1 8 bitsrelative delay 2 8 bits 8 bits relative delay (Nmeasure) 8 bits SectorID order Tx sector1 ID1 6 bits Tx Antenna1 ID1 2 bits Rx sector1 ID1 6bits Rx antenna1 ID1 2 bits Tx sector2 ID2 6 bits Tx Antenna2 ID2 2 bitsRx sector2 ID2 6 bits Rx antenna2 ID2 2 bits Tx sector ID1(Nmeasure/Nbeam) 6 bits Tx antenna1 ID (Nmease/Nbeam) 2 bits Rx sectorID1 (Nmeasure/Nbeam) 6 bits Rx antenna1 ID (Nmease/Nbeam) 2 bits Txsector2 ID (Nmeasure/Nbeam) 6 bits Tx antenna2 ID (Nmease/Nbeam) 2 bitsRx sector2 ID (Nmeasure/Nbeam) 6 bits Rx antenna2 ID (Nmease/Nbeam) 2bitsOption 4 feed back best

TABLE 10B Option 4 feed back best Element ID Length SNR SNR1_eff;Cap_eff1 8 bits Channel Chan Meas 1 Ntaps × Ntx_beams × MeasurementN_rx_beams × 16 bits Tap Delay relative delay 1 8 bits relative delayNmeasure 8 bits Sector ID order Tx sector1 ID1 6 bits Tx Antenna1 ID1 2bits Rx sector1 ID1 6 bits Rx antenna1 ID1 2 bits Tx sector2 ID1 6 bitsTx Antenna2 ID1 2 bits Rx sector2 ID1 6 bits Rx antenna2 ID1 2 bits

Note that the differential and progressive feedback frames may be usedin this case as well.

eBRP Feedback for Configurations #2 Through #5 of FIGS. 15B-15E.

For Configuration #2:

-   -   This has both vertical and horizontal polarizations per antenna        which implies 2×2 feedback elements per time dimension.    -   In the exhaustive search method, the system is configured to        sweep all Vertical (V) or horizontal (H) beams at the initiator        and at the responder.        -   In one embodiment, the feedback is set up so that a            polarization at the transmitter identifies a 2-dimensional            measurement at the responder corresponding to the direct            polarization and the cross polarization.        -   In one embodiment, the receive polarizations are measured            and fed back separately as additional measurements.    -   For Configurations #3, #4, and #5, define an extra PAAs which        adds an extra eDMG antenna dimension or an extra measurement to        the embodiments discussed above.        -   Feedback elements may be added per additional PAA/eDMG            antenna or polarization dimension.

Baseband Channel Tracking and Feedback for Established Links

In the previous embodiments, the feedback needed for an enhanced BRPprocedure was described. In another embodiment, described is thefeedback needed for baseband precoding in a hybrid precoding scheme.Note that this is feedback that occurs after the analog beam setup. Thismay be after enhanced beam refinement in SU-MIMO transmission or afterthe MU-MIMO phase [8] in MU-MIMO transmission.

After the initial enhanced BRP and feedback, the AP may use the feedbackto create the baseband precoder. However, in scenarios where there is nochange in the analog beams needed, there may need to be an update of theeffective baseband channel. In one embodiment, the following proceduremay be used.

The initiator may announce that a baseband feedback update procedure isinitiated. This may be by a special frame or by placing a flag in theBRP setup frame.

The AP may then start the baseband measurement. One of the following maybe used. Option 1: A BRP setup frame may be sent by the initiator with aflag indicating that the both transmitter and receiver analog beamsselected should not be changed (or that a specific set of analog beamsmay be used). The STA may then feed back the effective channel for thosespecific beams. The analog beams may be set up for SU-MIMO or basebandMU-MIMO. The BRP setup frame may be optional in the case that the AP andSTA are known to be in the beam configuration desired. Option 2: A BRPsetup frame may be sent by the initiator indicating that the receiveranalog beams should not be changed (or a specific set of receiver analogbeams may be used). The initiator may sweep multiple Tx beamsdownselected during the MU-MIMO phase (assuming analog MU-MIMO) or theeBRP refinement phase (assuming SU-MIMO). The STA may then feed back theeffective channel for those specific beams. There may be a need toinclude the beam index with the TRN fields to enable the initiator toidentify the Tx beams in the feedback. This differs from Option 1 basedon the need to sweep a set of beams. Option 3: The initiator may sendchannel measurement frame(s) using the selected transmit-receive beam.The measurement frames may comprise a MIMO setup frame (to set up thedesired beam configurations) and an 802.11ay preamble with no datapresent (for the actual channel measurement. In one embodiment, thesetup frame and preamble frame may be combined. In some cases, themeasurement frames may comprise 802.11 Null Data Packet AnnouncementFrame(s) and/or a Null Data packet frame(s). In these cases, the actualmeasurement frame (e.g., the NDP frame) may use a special set oforthogonal Channel Estimation Fields (CEF) in the preamble to enable thereceiver to estimate the channel. This differs from the solutions inOption 1 and Option 2 that set the measurement fields after the packet(in the TRN field). The channel estimation fields may be orthogonal CEFfields transmitted simultaneously, or a single CEF field transmittedrepeatedly.

The responder may then feed back the effective channel to the initiator.The feedback may be one or more of the following: Baseband feedbackassuming single carrier waveform; Baseband feedback assuming OFDM; orBaseband feedback assuming OFDMA. For baseband feedback assuming singlecarrier waveform, the STA may feed back a time-domain representation ofthe MIMO channel as in the earlier embodiments. For baseband feedbackassuming OFDM, the STA may feed back a frequency domain representationof the channel. 802.11ad/ay OFDM mode is made up of 336 data frequencytones. The feedback may be each individual tone or a single feedbackvalue representing a group of tones. Note that due to the beamformingeffect, the channel may be reasonably flat. In some embodiments, the APor STA may negotiate the tone grouping value. For baseband feedbackassuming OFDMA, the STA may feed back a frequency domain representationof a partial bandwidth of the channel. The BRP setup frame may requestfor a specific band. The bands requested may be less than 2.16 GHz ormay be in chunks of 2.16 GHz.

In some cases, the frame initiating the baseband feedback request maynot be heard (for example a case with multiple STAs in a beam-basedmulti-beam, multi-channel scenario). The initiator may fall back to aQuasi-Omni beam to send the setup frame then switch to the desiredconfiguration for measurement and feedback.

Procedure for Baseband Channel Tracking and Feedback for EstablishedLinks

Herein described is a baseband channel tracking and feedback procedurefor established links. The links may be for SU-MIMO transmission orMU-MIMO transmission.

For SU-MIMO transmission, this phase may be after an enhanced sectorlevel sweep and enhanced Beam Refinement. For MU-MIMO, this may be afterthe SISO phase and MU-MIMO phase.

This may be defined as a Phase 3 tracking procedure in which SISO orMIMO baseband tracking is performed, e.g., Phase 3 in the MU-MIMOBeamforming Protocol.

Note that as these are established links where the analog beams havebeen refined (for SU-MIMO or MU-MIMO), the feedback is for the basebandchannel given that the analog beams are fixed. Also, in someembodiments, the feedback may use frequency (for example bonded,aggregated, or OFDMA uplink transmission) or space (UL MU-MIMO) toimprove the feedback efficiency.

This phase may be comprised of a set-up sub-phase, a training sub-phaseand a polling/feedback sub-phase. This is illustrated in FIG. 17 forSU-MIMO transmission 240 and FIG. 18 for MU-MIMO transmission 250.

The sub-phases are described as follows.

For a Phase 3 Setup Sub-phase, there may be a set-up for a single userfor SU-MIMO, or for multiple users in MU-MIMO. A SU-MIMO setup frame mayindicate to the STA the receive antenna configuration desired and thenumber of transmit antennas and may be transmitted as a BRP setup frame(for options 1 or 2) or as an NDP announcement frame (option 3). AMU-MIMO setup frame may indicated the STAs that will be tracked, thecorresponding receive antenna configurations expected and the number ofTx sectors that will be trained.

In one embodiment, each STA may be polled independently to prepare itfor the training phase.

In one embodiment, the setup phase may be skipped. This may occur incases where the initiator and responder(s) are in the middle of atransmission.

In one embodiment, a group based ID (as used in Phase 1) may be set, butwith an indication of the expected receive antenna configuration. Theinformation transmitted may include:

-   -   TA: BSSID    -   RA: Group ID    -   Purpose: SU/MU-MIMO BF setup Phase 3    -   Sequence Number: identify which BF training (phase 3)    -   TX-Antennas/Selected Sectors/Simultaneous TX antennas        (Orthogonal Waveforms) training    -   Rx setup desired    -   BRP TRN-T        -   BRP₁: An (No of MUX ants in BRP frame 1), Ant index X_(i),            sector index S1, S2, . . . , Sn, Ant index X_(j), sector            index S1, S2, . . . , Sm, . . .        -   BRP_(k): An (No of MUX ants in BRP frame 1), Ant index            X_(i), sector index S1, S2, . . . , Sn, Ant index X_(j),            sector index S1, S2, . . . Sm, . . .

In one embodiment, an SU-MIMO/MU-MIMO setup ID (as used in Phase 2) maybe sent, but with an indication of the expected receive antennaconfiguration. The information transmitted may include:

-   -   RA: Group ID    -   TA: BSSID    -   Purpose: SU/MU-MIMO BF setup Phase 3    -   N: number of MU-MIMO Transmission Configurations    -   MU-MIMO Config_ID:        -   ID1: (BF1, TX Ant_Sec_ID1/SS_ID1, STA_ID1, RX Ant_Sec_ID1),        -   ID2: (BF2, TX Ant_Sec_ID2/SS_ID2, STA_ID2, RX Ant_Sec_ID2),

For a Phase 3 training sub-phase, the initiator may transmit the BRPtraining sequences based on the setup sub-phase.

As shown in FIG. 19 , for BRP based training 260, the initiator 210 maytransmit a BRP frame with TRN fields that sweep through Tx sectors withtraining fields for selected Tx sectors for a fixed Rx antennaconfiguration at full bandwidth. Note that the TRN fields for eachsector may train multiple Tx sectors by using orthogonal TRN sequences,i.e., a BRP frame for one Tx sector or multiple Tx sectors (withorthogonal waveforms). In some cases, the number Rx TRN should be fixedbased on the transmission configuration. In scenarios where there aremultiple MU-MIMO configurations in the setup frame, each configuration270 may be trained separately, as shown in FIG. 20 . Note that in caseswhere there may need to be some time given to the STA(s) to changeantenna/sector configuration, a dummy transmission or padding (e.g., STFor AGC) may be placed between each training sub-frame. In oneembodiment, this dummy transmission or padding may be mandatory. Inanother embodiment, this dummy transmission or padding may be optional,with the presence/absence of a padding field either blindly detected orsignaled in the setup frame.

For Null Data Packet based training, the initiator may transmit a NullData Packet frame with the EMDG CEF set to the CEF required forSU-MIMO/MU-MIMO transmission, and the initiator and responder EMDGantenna configurations set to the configurations for the desiredtransmission.

Note that in the training mode, other STAs that overhear thesetransmissions may opportunistically train their links based on thesectors chosen.

For a Phase 3 Feedback sub-phase 280, 290 shown in FIGS. 21A and 21Brespectively, this can be based on simple polling as in the Phase1/Phase 2 feedback. Such a procedure is illustrated in FIGS. 21A and21B. Given that beams are known (and especially if beam reciprocity isapplicable), efficiency may be improved by using: UL MU-MIMO/beam,and/or UL OFDMA, UL channel aggregation/bonding. This is illustrated inFIGS. 22 and 23 wherein a Phase 3 with a setup 290 and a Phase 3 with nosetup 300 are illustrated respectively.

Analog and Digital Baseband Tracking for 802.11ay

A consolidated BF training protocol for use during the DTI period of thebeacon interval was proposed for MU-MIMO beamforming in [1]. Theprotocol is comprised of:

-   -   Phase 1: SISO phase (mandatory)    -   Phase 2: MIMO phase (mandatory)

For SU-MIMO beamforming the following phases have also been proposed[2]:

-   -   Phase 1: Sector Level Sweep (SLS)    -   Phase 2: Tx-Rx Sector/antenna Mapping    -   Others: TBD

As disclosed herein, there is an analog and a digital baseband channeltracking a tracking phase to allow for tracking and channel updatepurposes, which uses a common framework for both SU-MIMO and MU-MIMOtracking.

In 802.11ad, the beam identification phases are: SLS, BRP, and BeamTracking.

Beam tracking is primarily for identifying the best beam fortransmission and is comprised of setup, training and feedbacksub-phases: setup, training, and feedback. An exemplary beam trackingprocedure 310 where an initiator 210 requests TRN-T is depicted in FIG.24 .

During a setup sub-phase, an initiator 210 requesting Tx beam trackingsets parameters in a transmitted packet, for example:

-   -   BEAM_TRACKING_REQUEST: Beam tracking requested    -   Packet Type: TRN-T-PACKET    -   TRN-LEN: number of TRN-T fields

During a training sub-phase, the initiator 210 may append an AGC fieldand TRN-T subfields to the packet.

During a feedback sub-phase, a responder 220 feeds back the channel tothe initiator 210. The feedback type may be the same as the feedbacktype in the last BRP frame that was transmitted from the initiator 210to the responder 220 with TX-TRN-REQ equal to 1. In some cases, if theresponder 220 has never received a BRP frame from the initiator 210 withTX-TRN-REQ equal to 1, the responder 220 may instead respond with thebest sector.

For 802.11ay, two types of beam tracking can be defined: Analog BeamTracking (AB); and Digital Baseband Channel Tracking (DBC).

AB tracking may be used to track the change in analog beams, such as dueto STA rotation or movement. This may be similar to 802.11ad tracking,but updated for SU/MU-MIMO.

DBC tracking may be used to track the change in the baseband channel fora fixed set of analog beams, such as due to beam blockage when usinghybrid beamforming. This may simplify tracking by simplifying setup andenabling use of CEF and a feedback request.

For 802.11ay, the beam tracking procedure may also be split into threephases: setup, training, and feedback. During setup, the procedure needsto signal the tracking type, and the antenna configuration needs to beset up. During training, the procedure may be based on the BRP (usingTRN-T fields) or null data packet (using the CEF). During feedback, thechannel feedback is needed for DBC tracking while any one of the bestbeam, SNR, or channel feedback is suitable for AB tracking. In FIG. 25 ,a block diagram 320 for an embodiment of beam tracking for 802.11ay, asset forth herein is depicted.

Beam Tracking Procedure.

Setup or Announcement. In the disclosed beam tracking for 802.11ay,during Setup or Announcement, the initiator 210 may indicate if there isan AB or DBC tracking request. For either type of tracking, there mayalso be an indication whether the procedure is SU or MU.

The setup may also include SU-MIMO/MU-MIMO BF setup, which may indicateinformation similar to the previously discussed MU-MIMO BF setupsub-phase. This may occur for either AB or DBC tracking. For DBCtracking cases, the setup may also indicate SU/MU transmissionconfiguration or use parameter to indicate keep current configuration.

The setup may also indicate the training type. For both AB and DBCtracking, the setup may indicate use of TRN-x and TRN_length, and setthe baseband precoder to the identity matrix. For DBC tracking only, thesetup may indicate the use of CEF based training and set the basebandprecoder to the identity matrix.

The setup may also indicate a feedback type required. For AB trackingonly, indicated feedback may include best beam(s) and SNR(s). For bothAB and DBC tracking, channel feedback may be indicated.

Training. The training may, for either AB or DBC tracking, be TRN-xbased training. The training may, for DBC tracking only, be CEF basedtraining.

Feedback. For either AB or DBC tracking, feedback may be based on simplepolling. In some embodiments, other methods such as UL-OFDMA orUL-MU-MIMO may be used for either AB or DBC tracking.

Generally, 802.11ay supports hybrid precoding (analog and digitalbaseband precoding) for SU and MU-MIMO. 802.11ay enables Analog BeamTracking and Digital Baseband Channel Tracking. Both the SU-MIMO and theMU-MIMO beamforming protocols have Analog Beam Tracking and DigitalBaseband Channel Tracking sub-phases.

Beam tracking enables an initiator or responder track the change in itsanalog or baseband beams without the need for the signaling and overheadin a BRP procedure. The signaling for beam tracking is sent in the DMGBRP packet header fields or EDMG header-A fields headers either asstandalone or piggy-backed data frames. Analog beam tracking trackschanges in the analog beams (and re-estimates the baseband beamformer ina hybrid beamforming transmission). Baseband beam tracking trackschanges in the baseband beamformer only in a hybrid beamformingtransmission.

A beam tracking initiator or beam tracking responder may requestbaseband beam tracking if at least one of the following conditions ismet: The performance of the system is degraded in a hybrid beamformingtransmission and the requestor would like to re-estimate the basebandchannel as part of the link adaptation procedure; The requestor did notrequest for detailed baseband channel information as part of the MIMOsetup procedure. In this case, the analog beams have been identified butthe information to design the baseband channel is still needed.

Beam tracking may be one of the following such as Initiator Receive BeamTracking. The initiator sends a request to the responder and theresponder sends a tracking packet to enable the initiator estimate itsreceive beams. In analog EDMG initiator receive beam tracking(illustrated in FIG. 26 ), the initiator seeks to track the analogreceive beams. In baseband EDMG initiator receive beam tracking(illustrated in FIG. 27 ), the initiator seeks to train the basebandchannel only using the reverse link. This is useful in the case thatthere is channel reciprocity and there is need to acquire the basebandchannel at the transmitter for hybrid beamforming without the need for alarge overhead feedback.

Beam tracking may also be Initiator Transmit Beam Tracking. Theinitiator sends a training packet to the receiver and the receiver feedsback the desired feedback (best beam, effective channel etc). In analogEDMG initiator transmit beam tracking (illustrated in FIG. 28 ), theinitiator seeks to track the analog transmit beams. In baseband EDMGinitiator transmit beam tracking (illustrated in FIG. 29 ), theinitiator seeks to train the baseband channel only using the forwardlink. This is useful in the case that there is no channel reciprocityand there is need to acquire the baseband channel at the transmitter forhybrid beamforming. Feedback is required in this case.

Beam tracking may also include Responder Receive Beam Tracking as inFIG. 30 . In this case, the initiator sends a training sequence to theresponder and asks it to track its receive beams. Note that there is nocorresponding baseband version.

The specific beam tracking type is set by parameters in the TXVECTOR andRXVECTOR and the signaling between the initiator and responder may takeplace in the packet headers of the packets transmitted between thetransmitter and receiver (i.e. the legacy BRP packet header and theEDMG-Header-A) or in special aggregated frames (e.g. the FBCK-REQUESTfield in the DMG Refinement element) based on the parameters in theTXVECTOR and RXVECTOR. Details will be shown in below.

An EDMG STA (beam tracking initiator) may request a peer EDMG STA (beamtracking responder) to perform receive beam tracking by setting, in atransmitted packet, the TXVECTOR parameter EDMG_BEAM_TRACKING_REQUEST toBeam Tracking Requested, EDMG_BEAM_TRACKING_TYPE to Analog Beam Trackingor Baseband Beam Tracking, BEAM_TRACKING_REQUEST to Beam Tracking NotRequested, EDMG_TRN_LEN, to the number of requested TRN subfields asdescribed, and packet type to TRN-R-PACKET. Otherwise, theEDMG_BEAM_TRACKING_REQUEST parameter shall be set to Beam Tracking NotRequested. If EDMG_BEAM_TRACKING TYPE is set to Baseband Beam Trackingand EMDG_TRN_LEN is set to zero, the parameter EDMG Extended CEF Numberof SS in the EDMG-Header-A shall be set to the TXVECTOR parameterEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED,

A beam tracking responder that receives a packet requesting beamtracking (corresponding to the BEAM_TRACKING_REQUEST orEDMG_BEAM_TRACKING_REQUEST parameter in the RXVECTOR set to Beam TrackRequested) and the Packet Type field in the PHY header equal to 0(corresponding to PACKET-TYPE field in the RXVECTOR set to TRN-R-PACKET)shall perform the tasks as described below.

For DMG Initiator Receive Beam Tracking: If BEAM_TRACKING_REQUESTparameter in the RXVECTOR is Beam Tracking Requested, there may be abeam refinement AGC field and TRN-R subfields appended to the followingpacket transmitted to the initiator in the same allocation, with an MCSindex greater than 0. The value of TXVECTOR parameter TRN-LEN in thefollowing packet from the responder to the initiator shall be equal tothe value of the TRN-LEN parameter in the RXVECTOR of the packet fromthe initiator.

For Analog and baseband EDMG Initiator Receive Beam Tracking: IfEDMG_BEAM_TRACKING_REQUEST parameter in the RXVECTOR is Beam TrackingRequested and the EDMG_BEAM_TRACKING_TYPE parameter in the RXVECTOR isAnalog Beam Tracking or Baseband Beam Tracking, there may be TRN-Rsubfields to the following packet transmitted to the initiator in thesame allocation, with an MCS index greater than 0. The value of TXVECTORparameter EDMG_TRN_LEN in the following packet from the responder to theinitiator shall be equal to the value of the EDMG_TRN_LEN parameter inthe RXVECTOR of the packet from the initiator.

For baseband EDMG Initiator Receive Beam Tracking: IfEDMG_BEAM_TRACKING_TYPE parameter in the RXVECTOR is Baseband BeamTracking and if EDMG_TRN_LEN=0 then no TRN-R subfields are appended tothe data packet. The baseband beamformer shall be set to a predeterminedorthogonal matrix e.g. the identity matrix, during the transmission ofthe preamble. The extended EDMG-CEF field is transmitted in the preambleand is used for decoding the data field of the packet and in measuringthe effective baseband channel. The value of TXVECTOR parameterEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED in the following packet from theresponder to the initiator shall be equal to the value of theEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED parameter in the RXVECTOR of thepacket from the intiator. The extended EDMG-CEF field shall beconstructed with its Nss set to theEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED parameter. Note thatEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED is always greater than or equalto the total number of data spatial streams. In a simple example, a STAmay be transmitting data with only one spatial stream but be able tosupport up to 4 spatial streams. The EDMG extended CEF Number of SS=4,and the Number of SS=1. In normal data transmission, the CEF isconstructed with Nss=1

In this scenario, the extended CEF is constructed with Nss=4. Thechannel estimation is done for the full Nss=4 channel but the resultingchannel is used to decode the data with Nss=1. What is shown is FIG. 31is Baseband beam tracking with no TRN-R fields. Extended EDMG-CEF isused for measurement.

If EDMG_BEAM_TRACKING_TYPE parameter in the RXVECTOR is Baseband BeamTracking and if EDMG_TRN_LEN=N, EDMG_TRN_P=P, EDMG_TRN_M=0 andEDMG_TRN_N=0, then N TRN-units are appended and are transmitted usingthe same AWV as the preamble and data field of the packet. The basebandbeamformer shall be set to a predetermined orthogonal matrix e.g. theidentity matrix, during the transmission of the appended TRN-R subfieldsonly and the measurement is based on the appended TRN-R packets. Thevalue of TXVECTOR parameter EDMG_TRN_LEN in the following packet fromthe responder to the initiator shall be equal to the value of theEDMG_TRN_LEN parameter in the RXVECTOR of the packet from the initiator.Additional solutions to signal this scenario may include one of threeoptions. In Option 1, Len=0, P=P, and M=N=0. In Option 2, Len=N, P=0,and M=N=0. In Option 3, Len=N, P=P, and M=N=0.

What is illustrated above is Baseband beam tracking with N TRN-R fields.Note that in FIG. 32 the N TRN R units are transmitted using the sameAWV as the preamble and data field of the packet.

If EDMG_BEAM_TRACKING_TYPE parameter in the RXVECTOR is not equal toBaseband Beam Tracking a responder may ignore a request for beamtracking within an allocation if no packets with an MCS index greaterthan 0 are transmitted from the responder to the initiator within theallocation.

If EDMG_BEAM_TRACKING_CONFIG parameter in the RXVECTOR is KeepConfiguration, then the responder(s) shall keep their antennaconfigurations for the duration of the tracking procedure. Note that inone solution, this may be signaled by setting EDMG_TRN_M=0 andEDMG_TRN_N=0. If EDMG_BEAM_TRACKING_CONFIG parameter in the RXVECTOR isChange Configuration, then the responder(s) shall change their antennaconfigurations for the duration of the tracking procedure. In onesolution, the responder shall change its configuration based oninformation sent in a MIMO configuration frame such as a BF Selectionframe. In another solution, the responder shall change it configurationbased on information sent in the EDMG Header-A. For MU PPDU (non-FDMA),this may be the SS Descriptor Set as shown below:

EDMG-Header-A Field Structure and 1 Definition for a MU PPDU (Non-FDMA)

TABLE 12 Number Field of bits Description SS Descriptor Set I, 9Describes the SS assignment to the ith I = 0, . . . , 7 STA addressedwithin the MU PPDU. This field is formatted as described in the tablebelow.SS Descriptor Set: where number of SS is number in the table 13 below.

TABLE 13 AID Number of SS 8 1

For MU PPD (FDMA), the Channel Descriptor set may be shown as below intable 12: EDMG-Header-A field structure 1 and definition for a MU PPDU(FDMA)

TABLE 14 Number Field of bits Description Channel 16 Describes the STAassignment for the Descriptor next channel, if present, after the ichannel indicated by the Channel Descriptor 2 field. This field isformatted as described in the table below.

TABLE 15 AID Number of SS Beamformed Reserved 8 1 1 6

The detailed settings for the TXVECTOR and RXVECTOR parameters, thepacket headers and the packet structures are shown in FIG. 33 (depictingTXVECTOR/RXVECTOR settings, packet header signaling and packet structurefor Analog EDMG Initiator Receive Beam Tracking) and FIG. 34 (depictingTXVECTOR/RXVECTOR settings, packet header signaling and packet structurefor Baseband EDMG Initiator Receive Beam Tracking) for analog trackingand for digital tracking. In FIG. 33 , the TXVECTOR/RXVECTOR settingsinclude EDMG_BEAM_TRACKING_REQUEST=Beam Tracking Requested,EDMG_BEAM_TRACKING_TYPE=analog beam tracking, BEAM_TRACKING_REQUEST=BeamTracking Not Requested, TRN-LEN=0, EDMG_TRN_LENGTH=N, packet type=0,TRN-R-PACKET, EDMG_BEAM_TRACKING_CONFIG=xx, andEDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED=xx The TXVECTOR/RXVECTOR settingsinclude Beam Tracking Request Field=0, a Packet Type Field 0 (BRP-RX),Training Length Field=0, EDMG TRN Length=N, RX TRN Units per Each TX TRNUnit=xx, EDMG TRN-UNIT-P=xx, EDMG TRN-UNIT M=xx, EDMG TRN-UNIT N-xx,EDMG Beam Tracking Request=1, requested, EDMG Beam Tracking RequestType=0, analog beam tracking; EDMG Beam Tracking Configuration=xx, andEDMG Extended CEF Number of SS=xx.

In FIG. 34 , the TXVECTOR/RXVECTOR settings include,EDMG_BEAM_TRACKING_TYPE=baseband beam tracking, EDMG_TRN_LENGTH=0,N,EDMG_BEAM_TRACKING_CONFIG=0/1, and EDMG_NUMBERT_OF_SPATIAL STREAMSTRACKED=Nss. The TXVECTOR/RXVECTOR settings also include EDMG TRNLength=0, N, RX TRN-Units per Each TX TRN UNIT=xx, EDMG TRN-UNIT-P=P,EDMG TRN-UNIT M=0, EDMG TRN-UNIT N=0, EDMG Beam Tracking Request=1,requested, EDMG Beam Tracking Request Type=1, baseband beam tracking,EDMG Beam tracking Configuration=0/1, and EEDMG Extended CEF Number ofSS=Nss. The TXVECTOR/RXVECTOR settings also include EDMG Beam TrackingRequest=0, Not requested, and EDMG Beam tracking Configuration=xx

A beam tracking initiator requesting transmit beam tracking shalleither: Set the BEAM_TRACKING_REQUEST parameter in the TXVECTOR to BeamTracking Requested, Packet Type to TRN-T-PACKET, TRN-LEN to the numberof TRN-Units as described herein, and append an AGC field and TRN-Tsubfields to the packet; or set the EDMG_BEAM_TRACKING_REQUEST parameterin the TXVECTOR to Beam Tracking Requested, EDMG_BEAM_TRACKING_TYPE toAnalog Beam Tracking or Baseband Beam Tracking, BEAM_TRACKING_REQUEST toBeam Tracking Not Requested, Packet Type to TRN-T-PACKET, andEDMG_TRN_LEN, EDMG_TRN_P, EDMG_TRN_M and EDMG_TRN_N as described herein,and append TRN-T subfields to the packet,

If EDMG_BEAM_TRACKING_TYPE parameter in the TXVECTOR is Baseband BeamTracking and EDMG_TRN_LEN=0 then no TRN-T subfields are appended. Thebaseband beamformer shall be set to a predetermined orthogonal matrixe.g. the identity matrix, during the transmission of the preamble. Theextended EDMG-CEF field is transmitted in the preamble and is used fordecoding the data field of the packet and in measuring the effectivebaseband channel. The extended EDMG-CEF field shall be constructed withits Nss set to the EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED parameter Notethat EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED is always greater than orequal to the total number of data spatial streams.

What is shown in FIG. 35 is Baseband beam tracking with no TRN-T fields.Extended EDMG-CEF is used for measurement.

If EDMG_BEAM_TRACKING_TYPE parameter in the TXVECTOR is Baseband BeamTracking and if EDMG_TRN_LEN=N, EDMG_TRN_P=P, EDMG_TRN_M=0 andEDMG_TRN_N=0, then N TRN units are appended to the data packet and aretransmitted using the same AWV as the preamble and data field of thepacket. The baseband beamformer shall be set to a predeterminedorthogonal matrix e.g. the identity matrix, during the transmission ofthe appended TRN-T subfields only and the measurement is based on theappended TRN-T subfields. Additional solutions to signal this scenariomay include three options. In one option, Len=0, P=P, and M=N. Inanother option, Len=N, P=0, and M=N. In still another option, Len=N,P=P, and M=N=0.

What is illustrated in FIG. 36 is Baseband beam tracking with N TRN-Tfields. Note that the N TRN-T units are transmitted using the same AWVas the preamble and data field of the packet.

If EDMG_BEAM_TRACKING_CONFIG parameter in the TXVECTOR is set KeepConfiguration, then the initiator shall keep its antenna configurationfor the duration of the tracking procedure.

If EDMG_BEAM_TRACKING_CONFIG parameter in the TXVECTOR is ChangeConfiguration, then the initiator shall change its antennaconfigurations for the duration of the tracking procedure. In onesolution, the initiator shall change its configuration based oninformation sent in a MIMO configuration frame such as a BF Selectionframe. In another solution, the initiator shall change it configurationbased on information sent in the EDMG Header-A. For a MU PPDU(non-FDMA), this may be the SS Descriptor Set as shown below:EDMG-Header-A field structure and 1 definition for a MU PPDU (non-FDMA)

TABLE 16 Number Field of bits Description SS Descriptor Set I, 9Describes the SS assignment to the ith I = 0, . . . , 7 STA addressedwithin the MU PPDU. This field is formatted as described in the tablebelow.

SS Descriptor Set: where number of SS is number in the table below plusone.

TABLE 17 AID Number of SS 8 1

For a MU PPD (FDMA), this may be the Channel Description set as shownbelow: EDMG-Header-A field structure 1 and definition for a MU PPDU(FDMA)

TABLE 18 Number Field of bits Description Channel 16 Describes the STAassignment for the Descriptor next channel, if present, after the ichannel indicated by the Channel Descriptor 2 field. This field isformatted as described in the table below.

TABLE 19 AID Number of SS Beamformed Reserved 8 1 1 6

The beam tracking responder may append the feedback to any packet fromthe responder to the initiator. The initiator may allocate time for thefeedback through a reverse direction grant, provided the reversedirection protocol is supported by both the initiator and responder. Thefeedback type shall be the same as the feedback type in the last BRPframe that was transmitted from the initiator to the responder withTX-TRN-REQ equal to 1.

If the responder has never received a BRP frame from the initiator withTX-TRN-REQ equal to 1, and If BEAM_TRACKING_REQUEST parameter in theRXVECTOR is Beam Tracking Requested, or if EDMG_BEAM_TRACKING_REQUESTparameter in the RXVECTOR is Beam Tracking Requested andEDMG_BEAM_TRACKING_TYPE is Analog Beam Tracking, the responder shallrespond with all subfields of the FBCK-TYPE field equal to 0 and set theBS-FBCK field to the index of the TRN-T subfield that was received withthe best quality.

With Option 1: send FBCK-REQ. This is not typical because tracking doesnot add to data but most general—If EDMG_BEAM_TRACKING_REQUEST parameterin the RXVECTOR is Beam Tracking Requested and EDMG_BEAM_TRACKING_TYPEis Baseband Beam Tracking, the initiator shall include a FBCK-REQ in aDMG Beam Refinement element and request for the feedback needed. Theresponder shall respond with the requested feedback.

Option 2: use MIMO feedback frame. If EDMG_BEAM_TRACKING_REQUESTparameter in the RXVECTOR is Beam Tracking Requested andEDMG_BEAM_TRACKING_TYPE is Baseband Beam Tracking, the responder shallsend a MIMO BF Feedback frame to the initiator.

The EDMG Channel Measurement Feedback element in the MIMO BF Feedbackframe shall contain the SU-MIMO beamforming training feedback for theinitiator SU-MIMO Beamforming Training subphase according to thefeedback type specified by the initiator in the SU-MIMO BF setupsubphase during SU MIMO setup.

The EDMG Channel Measurement Feedback element in the MIMO BF Feedbackframe shall contain the MU-MIMO beamforming training feedback accordingto the feedback type specified by the initiator in the MU-MIMO BFFeedback Poll subphase during MU MIMO setup.

With Option 3: create a default method. N-taps parameter may be added tothe EDMG Header-A—The responder shall respond with all subfields of theFBCK-TYPE field equal to 0 except for the channel measurement presentset to 1, the number of taps present set to a pre-determined value e.g.0×0 (1 tap) or signaled (e.g. EMDG Feedback number of taps Requested),the number of measurements based on the MIMO configuration and feed backthe channel measurements and corresponding tap delays for the channel.Alternatively, the receiver selects thereafter the set of taps that ismeasured around the tap with the largest amplitude according todot11ChanMeasFBCKNtaps. In this case, the additional signaling is notneeded.

The detailed settings for the TXVECTOR and RXVECTOR parameters, thepacket headers and the packet structures are shown in figure (x) foranalog tracking and figure (x) for digital tracking.

A beam tracking responder that receives a packet with RXVECTOR parameterEDMG_BEAM_TRACKING_REQUEST equal to Beam Tracking Not Requested,EDMG_BEAM_TRACKING_TYPE to Analog Beam Tracking,

BEAM_TRACKING_REQUEST equal to Beam Tracking Not Requested, TRN-LENequal to zero, Packet Type equal to TRN-R-PACKET, and EDMG_TRN_LEN to anonzero value and may use the TRN-R subfields appended to the receivedpacket to perform receive beam training. FIG. 37 illustratesTXVector/RXVector settings, packet header signaling, and packetstructure for Analog EDMG Responder Receive Beam Tracking. TheTXVector/RXVector settings for FIG. 37 includeEDMG_BEAM_TRACKING_REQUEST=Beam Tracking Requested,EDMG_BEAM_TRACKING_TYPE=analog beam tracking, BEAM_TRACKING_REQUEST=BeamTracking not Requested, packet type=TRN-T-PACKET, EDMG_TRN_LEN,EDMG_TRN_P, EDMG_TRN_M, EDMG_TRN_N, EDMG_BEAM_TRACKING_CONFIG=xx, andEDMG NUMBER OF SPATIAL STREAMS TRACKED=xx. The TXVector/RXVectorsettings also include Beam Tracking Request Field=0, Training LengthField=0, EDMG TRN Length=N, RX TRN-Units per Each TX TRN UNIT=TX_RX,EDMG TRN-UNIT-P=P, EDMG TRN-UNIT M=M, EDMG TRN-UNIT N=N, EDMG BeamTracking Request Type=0, analog beam tracking, EDMG Beam trackingConfiguration=xx, and EDMG NUMBER OF SPATIAL STREAMS TRACKED=xx. TheTXVECTOR/RXVECTOR settings include EDMG TRN Length=0, RX TRN-Units pereEach TX TRN UNIT=xx, EDMG TRN-UNIT-P=xx, EDMG TRN-UNIT M=xx, EDMGTRN-UNIT N=x, EDMG Beam Tracking Request=0, not requested, EDMG BeamTracking Request Type-xx, analog beam tracking, EDMG Beam TrackingConfiguration=xx, and EDMG NUMBER OF SPATIAL STREAMS TRACKED=xx. TheTXVector/RXVector settings also include Beam Tracking Request Field=0,Packet Type Field=Reserved, and Training Length Field=Reserved.

FIG. 38 illustrates TXVector/RXVector settings, packet header signalingand packet structure for a Baseband EDMG Initiator Transmit BeamTracking. The TXVector/RXVector settings includeEDMG_BEAM_TRACKING_REQUEST=Beam Tracking Requested,EDMG_BEAM_TRACKING_TYPE-analog beam tracking, BEAM_TRACKING_REQUEST=BeamTracking not Requested, TRN-LEN=0, packet type=TRN-T-Packet,EDMG_TRN_LEN=N, EDMG_TRN_P=0/PN, EDMG_TRN_M=0, EDMG_TRN_N=0,EDMG_BEAM_TRACKING_CONFIG=0/1, and EDMG NUMBER OF SPATIAL STREAMSTRACKED=Nss. The TXVector/RXVector settings also include EDMG_TRN_P=0/P,Beam Tracking Request Field=0, Training Length Field=Reserved, EDMG TRNLength=N, RX TRN-Units per Each TX TRN UNIT=TX_RX, EDMG TRN-UNIT-P=0/N,EDMG TRN-UNIT M=0, EDMG TRN-UNIT N=0, EDMG Beam Tracking Request Type=0,baseband beam tracking, EDMG Beam tracking Configuration=0/1, and EDMGExtended CEF Number of SS=Nss. The TXVector/RXVector settings alsoinclude EDMG TRN Length=0, RX TRN-Units per Each TX TRN UNIT=xx, EDMGTRN-UNIT-P=xx, EDMG TRN-UNIT M=xx, EDMG TRN-UNIT N=x, EDMG Beam TrackingRequest=0, not requested, EDMG Beam Tracking Request Type=xx, EDMG Beamtracking Configuration=xx, and EDMG Extended CEF Number of SS=xx. TheTXVector/RXVector settings also include Beam Tracking Request Field=0,Packet Type Field=Reserved, and Training Length Field=Reserved. TheFeedback type may be as a last BRP frame, Explicit Request, or bydefault. The feedback method may be by piggyback and reverse directiongrant (RD protocol).

FIG. 39 illustrates TXVector/RXVector settings, packet header signalingand packet structure for an Analog EDMG Responder Receive Beam Tracking.The TXVector/RX vector settings include EDMG_BEAM_TRACKING_REQUEST=BeamTracking Not Requested, EDMG_BEAM_TRACKING_TYPE=analog beam tracking,BEAM_TRACKING_REQUEST=Beam Tracking not Requested, TRN-LEN=0, packettype=TRN-R-PACKET, EDMG_TRN_LEN=N, EDMG_BEAM_TRACKING_CONFIG=xx, and DMGNUMBER OF SPATIAL STREAMS TRACKED=xx. The TXVector/RXVector settingsalso include a Beam Tracking Request Field=0 and a Training LengthField=0. The TXVector/RXVector settings also include EDMG TRN Length=N,RX TRN-Units per Each TX TRN UNIT=xx, EDMG TRN-UNIT-P=xx, EDMG TRN-UNITM=xx, EDMG TRN-UNIT N=xx, EDMG Beam Tracking Request=1, requested, EDMGBeam Tracking Request Type=1, analog beam tracking, EDMG Beam trackingConfiguration=xx, and EDMG Extended CEF Number of SS=xx.

The TXVector and RXVector parameters needed for beam tracking are shownin Table (21)

TABLE 20 parameter Condition Value TXVECTOR RXVECTOREDMG_BEAM_TRACKING_TYPE FORMAT This parameter indicates if analog beam YY is EDMG tracking or baseband beam tracking is requested Enumeratedtype: Analog beam Tracking or Baseband Beam TrackingEDMG_BEAM_TRACKING_CONFIG FORMAT This parameter indicates if thetracking procedure Y Y IS EDMG should use the current configuration orshould read the data packet to switch to a different configurationEnumerated type: Keep configuration or change configuration

TABLE 21 EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED FORMAT This parameterindicates the number of IS EDMG spatial streams that should be used inan extended EDMG CEF during baseband beamforming. For SU-MIMO, itindicates the maximum number of SS that may be transmitted with thegiven antenna configuration. For MU-MIMO, it indicates the total numberof SS that may be transmitted to all the STAs with the given antennaconfiguration. Enumerated type: Integer from 0 to 7EDMG_NUMBER_OF_FEEDBCK_TAPS_REQUESTED_TRACKING FORMAT This parameterindicates the default Y Y IS EDMG number of channel taps to be fed backin baseband channel feedback Enumerated type: 1 tap, 5 taps, 15 taps, 63taps

The EDMG_TRN_LEN parameter in the TVXVECTOR or RXVECTOR of an EDMG BRPpacket shall be greater than zero except when baseband beam tracking isenabled (EDMG_BEAM_TRACKING_REQUEST parameter in the TXVECTOR is BeamTracking Requested and EDMG_BEAM_TRACKING_TYPE is Baseband BeamTracking). The definition for the EDMG-Headers for tracking in EDMG SCmode and EDMG OFDM mode PPDUs are shown in Table (x) below

TABLE 22 Number Start Field Name of bits bit Description EDMG Beam 1 91Corresponds to the TXVECTOR parameter TrackingEDMG_BEAM_TRACKING_REQUEST. Used in combination with Request EDMG BeamTracking Request Type with corresponding TXVECTOR parameterEDMG_BEAM_TRACKING_TYPE. Set to 1 to indicate the need for beam tracking(10.38.7); otherwise, set to 0. The EDMG Beam Tracking Request field isreserved when the EDMG TRN Length field is 0 and EMDG Beam TrackingRequest Type is 0 EDMG Beam 1 95 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_TYPE. Request Type Set to 0 to indicateAnalog Beam Tracking (10.38.7) Set to 1 to indicate Baseband BeamTracking (10.38.7) EDMG Beam 1 96 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_CONFIG. Config Set to 0 to indicate changeantenna configuration (10.38.7) Set to 1 to indicate keep antennaconfiguration (10.38.7) EDMG 3 101 Corresponds to the TXVECTOR parameterExtended EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED. CEF Number Used whenEDMG_BEAM_TRACKING_TYPE is equal to Baseband of SS Beam Tracking andEDMG_TRN_N is set to zero. This implies baseband beam tracking is doneusing the transmitted extended EDMG CEF The value of this field plus oneindicates the number of SSs sounded when using the extended CEF inbaseband tracking. Reserved 12 102 Set to 0 by the transmitter andignored by the receiver. EMDG 2 98 Number of taps in each channelmeasurement: Feedback 0x0 - 1 tap number of 0x1 - 5 taps taps 0x2 - 15taps Requested 0x3 - 63 taps

For non-FMDA tracking, a beam tracking request frame may be sent to allthe STAs. A new EDMG-header-B may be defined to signal the information.Alternatively, each STA may undergo an SU-MIMO beam tracking requestindividually.

For FMDA tracking, a beam tracking request may be made per STA with thetracking request done within the assigned frequency. In one option, thesignaling may be done in the EDMG-Header A and applies to all STAs. Inone solution, a STA specific tracking may be done by transmitting on theEDMG-header-B. This allows channel identification for a single STA in adefined frequency bandwidth that is less than the transmissionbandwidth.

For MU-MIMO PPDU-FDMA, two structures may be possible. With an extendedEDMG-CEF, all the STAs in the FDMA group have to use the same EDMG-CEFsize. If you use appended TRN-units, two options may be available. Oneoption may be to transmit TRN units on all frequency bands. Anotheroption may be to transmit TRN units of frequency band of a desired STAonly. An EDMG Header and field structure and 1 definition for a MU PPDU(FDMA or non-FMDA) is shown below

TABLE 23 Number Start Field Name of bits bit Description EDMG Beam 1 66Corresponds to the TXVECTOR parameter TrackingEDMG_BEAM_TRACKING_REQUEST. Used in combination with Request EDMG BeamTracking Request Type with corresponding TXVECTOR parameterEDMG_BEAM_TRACKING_TYPE. Set to 1 to indicate the need for beam tracking(10.38.7); otherwise, set to 0. The EDMG Beam Tracking Request field isreserved when the EDMG TRN Length field is 0 and EMDG Beam TrackingRequest Type is 0 EDMG Beam 1 67 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_TYPE. Request Type Set to 0 to indicateAnalog Beam Tracking (10.38.7) Set to 1 to indicate Baseband BeamTracking (10.38.7) EDMG Beam 1 68 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_CONFIG. Config Set to 0 to indicate changeantenna configuration (10.38.7) Set to 1 to indicate keep antennaconfiguration (10.38.7) EDMG 3 69 Corresponds to the TXVECTOR parameterExtended EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED. CEF Number Used whenEDMG_BEAM_TRACKING_TYPE is equal to Baseband of SS Beam Tracking andEDMG_TRN_N is set to zero. This implies baseband beam tracking is doneusing the transmited extended EDMG CEF The value of this field plus oneindicates the number of SSs sounded when using the extended CEF inbaseband tracking. Reserved 40 72 Set to 0 by the transmitter andignored by the receiver. EMDG 2 98 Number of taps in each channelmeasurement: Feedback 0x0 - 1 tap number of 0x1 - 5 taps taps 0x2 - 15taps Requested 0x3 - 63 taps

An EDMG Header, field structure and definition is shown in table (x)below

TABLE 24 Number Start Field Name of bits bit Description EDMG Beam 1 24Corresponds to the TXVECTOR parameter TrackingEDMG_BEAM_TRACKING_REQUEST. Used in combination with Request EDMG BeamTracking Request Type with corresponding TXVECTOR parameterEDMG_BEAM_TRACKING_TYPE. Set to 1 to indicate the need for beam tracking(10.38.7); otherwise, set to 0. The EDMG Beam Tracking Request field isreserved when the EDMG TRN Length field is 0 and EMDG Beam TrackingRequest Type is 0 EDMG Beam 1 25 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_TYPE. Request Type Set to 0 to indicateAnalog Beam Tracking (10.38.7) Set to 1 to indicate Baseband BeamTracking (10.38.7) EDMG Beam 1 26 Corresponds to the TXVECTOR parameterTracking EDMG_BEAM_TRACKING_CONFIG. Config Set to 0 to indicate changeantenna configuration (10.38.7) Set to 1 to indicate keep antennaconfiguration (10.38.7) EDMG 3 27 Corresponds to the TXVECTOR parameterExtended EDMG_NUMBER_OF_SPATIAL_STREAMS_TRACKED. CEF Number Used whenEDMG_BEAM_TRACKING_TYPE is equal to Baseband of SS Beam Tracking andEDMG_TRN_N is set to zero. This implies baseband beam tracking is doneusing the transmited extended EDMG CEF The value of this field plus oneindicates the number of SSs sounded when using the extended CEF inbaseband tracking. Reserved 34 30 Set to 0 by the transmitter andignored by the receiver. EMDG 2 98 Number of taps in each channelmeasurement: Feedback 0x0 - 1 tap number of 0x1 - 5 taps taps 0x2 - 15taps Requested 0x3 - 63 taps

For a control mode PPDU, the L-Header field is the same as the DMGcontrol mode header field and the reserved bits 22 and 23 shall be bothset to 1. In this case, the Scrambler Initialization field in theL-Header is defined as shown in Table 8.

For an EDMG SC mode PPDU or an EDMG OFDM mode PPDU, the L-Header fieldis the same as the DMG SC mode PHY header with the following changes:the reserved bit 46 shall be set to 1 to indicate the presence of theEDMG-Header-A field. This implies that the PPDU is an EDMG PPDU; and thereserved bit 47 shall be set to 1 to indicate the beam tracking requesttype. This implies either analog or digital baseband channel trackingrequest; the Last RSSI field shall be redefined as shown in Table 10;and the 5 LSBs of the Length field shall be redefined as shown in Table11. Moreover, the remaining bits of the Length field shall be set sothat the spoofing error is smaller than one symbol block (512×Tc) andnon-negative, where spoofing error is defined as the difference betweenthe PPDU duration calculated based on L-Header and the actual PPDUduration.

An EDMG SC mode header fields are illustrated in table 25 below

TABLE 25 Number Start Field Name of bits bit Description Beam Tracking 138 Corresponds to the TXVECTOR parameter Request BEAM_TRACKING_REQUEST.Set to 1 to indicate the need for beam tracking (10.38.7); otherwise,set to 0. The Beam Tracking Request field is reserved when the TrainingLength field is 0 and the TXVECTOR parameter EDMG_BEAM_TRACKING_TYPE isAnalog Beam Tracking Beam Tracking 1 47 Corresponds to the TXVECTORparameter Request EDMG_BEAM_TRACKING_TYPE. Type Set to 0 to indicateAnalog Beam Tracking (10.38.7) Set to 1 to indicate Baseband BeamTracking (10.38.7)

Example Wireless-Communication Device

FIG. 40 depicts an example wireless-communication device, in accordancewith at least one embodiment. The device 1200 could be an AP, a STA,and/or any other wireless-communication device. Thus, any of the APs,STAs, and/or other computing-and-communication devices described herein(e.g., the AP 1102, the STAs 1110-1140, etc.) could have a structuresimilar to the example structure that is described in connection withFIG. 26 . Moreover, the various devices referred to herein by terms suchas initiator, responder, and the like could have a structure similar tothe structure described in connection with FIG. 26 .

As shown in FIG. 40 , the example device 1200 includes a communicationinterface 1202, a processor 1204, data storage 1206 containing programinstructions 1208, and an optional user interface 1210, all of which arecommunicatively connected by a system bus 1212. Other devicearchitectures could be used as well, as the provided and describedarchitecture is presented herein by way of example and not limitation.

The communication interface 1202 may include one or morewireless-communication interfaces (for communicating according to, e.g.,LTE, Wi Fi (i.e., any one or more IEEE 802.11 protocols), Bluetooth,and/or the like) and/or one or more wired-communication interfaces (forcommunicating according to, e.g., Ethernet, USB, and/or the like). Assuch, the communication interface 1202 may include any necessaryhardware (e.g., chipsets, antennas, Ethernet cards, etc.), any necessaryfirmware, and any necessary software for conducting one or more forms ofcommunication with one or more other entities as described herein.

The processor 1204 may include one or more processors of any type deemedsuitable by those of skill in the relevant art, some examples includinga general-purpose microprocessor and a dedicated digital signalprocessor (DSP).

The data storage 1206 may take the form of any non-transitorycomputer-readable medium or combination of such media, some examplesincluding flash memory, read-only memory (ROM), and random-access memory(RAM) to name but a few, as any one or more types of non-transitorydata-storage technology deemed suitable by those of skill in therelevant art could be used. The data storage 1206 contains programinstructions 1208 that are executable by the processor 1204 for carryingout various functions described herein.

When present, the optional user interface 1210 may include one or moreinput devices (a.k.a. components and the like) and/or one or more outputdevices (a.k.a. components and the like). With respect to input devices,the optional user interface 1210 may include one or more touchscreens,buttons, switches, knobs, microphones, and the like. With respect tooutput devices, the optional user interface 1210 may include one or moredisplays, speakers, light emitting diodes (LEDs), and the like.Moreover, one or more components (e.g., an interactivetouchscreen-and-display component) of the optional user interface 1210could provide both user-input and user-output functionality. Andcertainly other user-interface components could be used in a givencontext, as known to those of skill in the art.

FIG. 41 depicts a beam tracking method for 802.11ay with respect to theinitiator 210. The method 1300 may comprise generating at an initiatordevice a beam-forming training packet having a precoded setup field anda non-precoded channel estimation field at step 1310. The setup field isconfigured to have a digital baseband channel (DBC) tracking indicatorparameter. At step 1320, the beam-forming training packet is transmittedusing pre-determined analog beam coefficients. Further, at step 1330,the initiator 210 receives from the responder 220 a feedback messagehaving transmitter precoder data based on a DBC estimate formed by theresponder 220.

FIG. 42 depicts a beam tracking method for 802.11ay with respect to theresponder 220. The method 1400 may receiving a training packet by theresponder 220 having multiple antennas and responsively generating abeam-formed receive signal by processing the received training packetwith previously determined analog beam coefficients at step 1410. Next,the responder 220 determines whether DBC tracking is indicated based ona tracking-type parameter contained within the received training packetat step 1420. At step 1430, the responder 220 processes a non-precodedtraining signal within the beam-formed receive signal and responsivelydetermines a DBC estimate. Next, at step 1440, the responder 220provides a feedback message having transmitter precoder data based onthe DBC estimate.

ADDITIONAL NOTES

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

Although the embodiments described herein consider 802.11 specificprotocols, it is understood that the embodiments described herein arenot restricted to this scenario and are applicable to other wirelesssystems as well.

Throughout the embodiments and provided examples, the blank areas in thefigures generally imply that there is no restriction for this area andany embodiment can be employed.

What is claimed is:
 1. A method implemented by a wirelesstransmit/receive unit (WTRU) having multiple antennas, the methodcomprising: determining information that is associated with a basebandchannel, the information indicating any of: measurement information andchannel information; and transmitting a signal for requesting basebandbeam tracking, the signal transmission based on a determination thatsystem performance is degraded in a beamforming transmission andre-estimation of the baseband channel is part of a current linkadaptation procedure.
 2. A method implemented by a wirelesstransmit/receive unit (WTRU) having multiple antennas, the methodcomprising: determining information that is associated with a basebandchannel, the information indicating any of: measurement information andchannel information; and transmitting a signal for requesting basebandbeam tracking, the signal transmission based on a determination thatdetailed baseband channel information was not part of a multiple-inmultiple-out (MIMO) setup procedure.
 3. The method of claim 2, whereintransmitting a signal for requesting baseband beam tracking occurs in aninstance when analog beams have been identified but information for thebaseband channel is still needed.
 4. The method of claim 1, wherein thesignal for requesting baseband beam tracking includes a training packetincluding information indicating a beam tracking type to be any ofanalog beam tracking and digital beam tracking.
 5. The method of claim1, wherein the signal for requesting baseband beam tracking includes anon-precoded training signal within a beam-formed signal.
 6. The methodof claim 5, wherein the non-precoded training signal comprises trainingsequences.
 7. The method of claim 5, wherein the beam-formed signalincludes a use parameter that indicates maintaining a currentconfiguration for the beam-formed signal.
 8. The method of claim 5,wherein the non-precoded training signal comprises a channel estimationfield (CEF).
 9. The method of claim 8, wherein the CEF is transmittedafter a padding interval of a training packet.
 10. The method of claim5, wherein the CEF is contained in a setup header of a training packet.11. A wireless transmit/receive unit (WTRU) comprising a processor, atransmitter, and a receiver, wherein the processor, the transmitter, andthe receiver are configured to: determine information that is associatedwith a baseband channel, the information indicating any of: measurementinformation and channel information; and transmit a signal forrequesting baseband beam tracking, the signal transmission based on adetermination that system performance is degraded in a beamformingtransmission and re-estimation of the baseband channel is part of acurrent link adaptation procedure.
 12. The WTRU of claim 11, wherein thesignal for requesting baseband beam tracking includes a training packetincluding information indicating a beam tracking type to be any ofanalog beam tracking and digital beam tracking.
 13. The WTRU of claim11, wherein the signal for requesting baseband beam tracking includes anon-precoded training signal within a beam-formed signal.
 14. The WTRUof claim 13, wherein the non-precoded training signal comprises trainingsequences.
 15. The WTRU of claim 13, wherein the beam-formed signalincludes a use parameter that indicates maintaining a currentconfiguration for the beam-formed signal.
 16. The WTRU of claim 13,wherein the non-precoded training signal comprises a channel estimationfield (CEF).
 17. The WTRU of claim 16, wherein the CEF is transmittedafter a padding interval of a training packet.
 18. The WTRU of claim 16,wherein the CEF is contained in a setup header of a training packet.